Testing And Adjusting

Usage:

Introduction

NOTE: For Specifications with illustrations, make reference to Specifications For G3306 Truck Engine. If the Specifications are not the same as in the Systems Operation, Testing and Adjusting, look at the printing date on the back cover of each book. Use the Specifications given in the book with the latest date.

Troubleshooting

Troubleshooting can be difficult. The Troubleshooting Index gives a list of possible problems. To make a repair to a problem, make reference to the cause and correction on the pages that follow.

This list of problems, causes, and corrections will only give an indication of where a possible problem can be, and what repairs are needed. Normally, more or other repair work is needed beyond the recommendations in the list.

Remember that a problem is not normally caused only by one part, but by the relation of one part with other parts. This list is only a guide and cannot give all possible problems and corrections. The serviceman must find the problem and its source, then make the necessary repairs.

NOTE: For each problem, a list of possible causes and corrections is given. The list of probable causes and corrections should be performed in numeric sequence.

1. Engine Crankshaft Will Not Turn When Ignition Switch Is On

2. Engine Hard To Or Will Not Start

3. Engine Misfiring Or Running Rough

4. Engine Stall At Low RPM

5. Low Power

6. Engine Speed Is Not Stable

7. Too Much Vibration

8. Loud Combustion Noise (Sound)

9. Valve Train Noise

10. Oil In Cooling System

11. Mechanical Noise (Knock) In Engine

12. Fuel Consumption Too High

13. Too Much Valve Lash

14. Little Or No Valve Lash

15. Oil At The Exhaust

16. Engine Has Excessive Early Wear

17. Coolant In Lubrication Oil

18. Too Much Exhaust Smoke At Normal Operation Temperatures (White, Black Or Blue Smoke)

19. Engine Has Low Oil Pressure

20. Engine Uses Too Much Lubrication Oil

21. Coolant Temperature Above Normal

22. Coolant Temperature Below Normal

23. Exhaust Temperature Is Too High

24. Starting Motor Does Not Turn

25. Alternator Gives No Charge

26. Alternator Charge Rate Is Low Or Not Regular

27. Alternator Charge Too High

28. Alternator Has Noise

29. Loss Of Coolant

30. Short Spark Plug Life

31. Pre-Ignition

32. Detonation

33. Gas Supply Line Shutoff Valve Failure

Engine Crankshaft Will Not Turn When Ignition Switch Is On

Probable Cause(s):

* Low Or No Battery Voltage

* Faulty Switch, Wiring Or Connection In Switch Circuit

* Faulty Cable Or Connection (Battery To Starting Motor)

* Faulty Starting Motor Solenoid

* Faulty Starting Motor

* Transmission Problem Prevents Crankshaft From Turning

* Inside Problem Prevents Crankshaft From Turning

1. Low Or No Battery Voltage

Check battery voltage. If battery voltage is less than 8 volts for a 12 volt system, or 16 volts for a 24 volt system, put a charge on the battery. If battery will not hold a charge, load test the battery. Refer to the Electrical System of the Systems Operation, Testing And Adjusting module of this Service Manual.

2. Faulty Switch, Wiring Or Connection In Switch Circuit

With ignition switch in the "START" position, check voltage at switch connection on starting motor solenoid. If there is no voltage, or if the voltage is low at this connection and there is good voltage at the battery, check for a faulty cable or connection between the battery and the starting motor.

3. Faulty Cable Or Connection (Battery To Starting Motor)

With ignition switch in the "START" position, check voltage at connection of battery cable to starting motor. If there is no voltage, or if the voltage is low at this connection and there is good voltage at the battery, check for a faulty cable or connection between the battery and the starting motor.

4. Faulty Starting Motor Solenoid

Remove and repair or replace a solenoid which does not work when voltage is correct at both the battery and ignition switch connections.

5. Faulty Starting Motor

If the solenoid works and the starting motor does not turn the crankshaft, the starting motor is faulty. Before removing the starting motor, turn the crankshaft by hand to be sure a mechanical failure inside the engine, transmission is not preventing the crankshaft from turning. If the crankshaft turns freely by hand, engage the starting motor again. If the starting motor still will not work, remove the starting motor. Repair or replace the starting motor.

6. Transmission Problem Prevents Crankshaft From Turning

If the crankshaft cannot be turned by hand, disconnect the transmission. If the crankshaft will now turn, find the cause of the problem in the transmission and make necessary corrections.

7. Inside Problem Prevents Crankshaft From Turning

If the crankshaft cannot be turned after disconnecting the transmission, remove the spark plugs and check for fluid in the cylinders while turning the crankshaft. If fluid in the cylinders is not the problem, the engine must be disassembled to check for other internal problems. Some of the possible problems are bearing seizure, piston seizure, and valves making contact with the pistons.

Engine Hard To Or Will Not Start

Engine Crankshaft Turns Too Slowly

Probable Cause(s):

* Low Battery Voltage

* Faulty Cable Or Connection (Battery To Starting Motor)

* Oil Too Thick For Free Crankshaft Rotation

* Faulty Starting Motor

* Extra Outside Loads

* Mechanical Problem Inside Engine

1. Low Battery Voltage

Check battery voltage. If battery voltage is less than 8 volts for a 12 volt system, or 16 volts for a 24 volt system, put a charge on the battery. If battery will not hold a charge, load test the battery. Refer to Electrical System of the Systems Operation, Testing And Adjusting module of this Service Manual.

2. Faulty Cable Or Connection (Battery To Starting Motor)

3. Oil Too Thick For Free Crankshaft Rotation

Use the recommended Lubrication Viscosities as found in the Operation And Maintenance Manual.

4. Faulty Starting Motor

Remove and test starting motor. Make repairs as necessary or install a new starting motor.

5. Extra Outside Loads

Damage to the transmission can put extra load on the engine. This prevents free rotation of the crankshaft. To check, disconnect the transmission and start the engine.

6. Mechanical Problem Inside Engine

Disassemble the engine and check all components for damage.

Engine Crankshaft Turns Freely

Exhaust Smoke Can Be Seen While Starting (Go to Step 1)

Probable Cause(s):

* Cold Outside Temperatures

* Slow Cranking Speed

* Valve Adjustment Not Correct

* Low Compression

Exhaust Smoke Cannot Be Seen While Starting (Go to Step 5)

Probable Cause(s):

* No Fuel In Tank(s)

* Exhaust System Not Open

* No Fuel To Engine

* Ignition System Failure

* Gas Line Pressure Regulator Not Working

1. Cold Outside Temperature

It may be necessary to use starting aids, or to heat engine oil or coolant at temperature below 10°C (50°F).

2. Slow Cranking Speed

Cranking speed must be at least 225 rpm. Check the condition of the starting system.

3. Valve Adjustment Not Correct

Check and make necessary adjustments. Refer to the Systems Operation, Testing and Adjusting module of this Service Manual.

4. Low Compression

Refer to Engine Misfiring Or Running Rough.

Exhaust Smoke Cannot Be Seen While Starting

Probable Cause(s):

5. Exhaust system not open

Loosen the exhaust pipe from the exhaust manifold. If the engine will now start, check the exhaust system for damage and/or restrictions.

6. No Fuel To Engine

Check fuel supply and pressure regulator, reset shutoff valve in the supply line. Check carburetor throttle and linkage carburetor and governor actuator.

7. Ignition System Failure

Check the ignition transformers for loose connections, moisture, short or open circuits. Check the low and high tension wires. Check the spark plugs for correct type and spark plug adapters. Repair or replace any components that shows signs of failure.

8. Gas Line Pressure Regulator Not Working

Clean balance line. Check inlet and outlet regulator pressures.

Engine Misfiring Or Running Rough

Probable Cause(s):

* Valve Adjustment Not Correct

* Cylinder Head Gasket Leakage

* Valve Leakage, Wear Or Damage To Pistons And/Or Piston Rings, Wear Or Damage To Cylinder Walls

* Low Idle Rpm

* Governor Actuator Linkage

* Ignition System Failure

* Low Gas Pressure

1. Valve Adjustment Not Correct

Check and make necessary adjustments. Refer to the Systems Operation, Testing and Adjusting module of this Service Manual. Also check for a bent or broken push rod.

2. Cylinder Head Gasket Leakage

Leakage at the gasket of the cylinder head can show as an outside leak or can cause loss of coolant through the radiator overflow. Remove the radiator cap and with the engine running look for air bubbles in the coolant. Bubbles in the coolant are a sign of probable leakage at the head gasket. Remove the cylinder head from the engine. Check the cylinder head, cylinder walls and head gasket surface of the cylinder block for cracks. When installing the head, use a new head gasket. Refer to the Specifications module for the proper bolt tightening sequence.

3. Valve Leakage; Wear Or Damage To Pistons And/Or Piston Rings; Wear Or Damage To Cylinder Walls

If leakage is heard at the inlet manifold, the intake valves leak. If the leakage is heard at the exhaust manifold, the exhaust valves leak. Pistons or rings that have damage can be the cause of too much pressure in the crankcase. This condition can cause more than the normal amount of fumes (blow-by) coming from the crankcase breather. The 8T2700 Indicator Group is used to check the amount of blow-by. The test procedure is in Special Instruction, SEHS8712.

4. Low idle rpm

Check and make necessary adjustments. Refer to the Systems Operation, Testing And Adjusting module of this Service Manual.

5. Governor Actuator linkage

Check and make necessary adjustments. Refer to the Woodward Troubleshooting Guide.

6. Ignition System Failure

7. Low Gas Pressure

Check for leaks in gas supply. Check the line pressure regulator, shutoff valve and solenoid. Regulator pressure should not change over the normal load range. Check gas pressure before and after the line pressure regulator. Check for restrictions in balance line for carburetor to regulator.

Engine Stall At Low RPM

Probable Cause(s):

* Low Idle RPM Too Low

* Engine Accessories

1. Low Idle rpm Too Low

Calibrate the foot pedal by using the Woodward software.

2. Engine accessories

Check engine accessories for damage and make repair or replacement. If necessary, disconnect the accessories and test the engine.

Low Power

Probable Cause(s):

* Oil Level To High

* Restrictions And/Or Leaks In Air Inlet System

* Plugged Or Damaged Converter/Muffler

* Valve Adjustment Not Correct

* Turbocharger Has Carbon Deposits Or Other Cause Of Friction

* Low Gas Pressure

* Failure Of Ignition Wires

* Transformer Failure

* Faulty Spark Plugs

* Spark Plug Adapters Leak

* Governor Actuator Linkage

1. Oil Level Too High

Remove dip stick and check oil level. If level is too high, drain oil to bring the oil level to the desired level.

NOTE: An oil sample should be run to find out if the oil level is increasing due to a fuel leak or other engine problem.

2. Restrictions And Leaks In The Air Inlet System.

a. Check for leaks.

b. Check the pressure in the air inlet manifold.

c. Look for restrictions in the air cleaner.

d. Faulty air to air aftercooler. Check temperature of inlet and outlet air from air cooler. Remove any external or internal restrictions. Check for cracks.

3. Plugged Or Damaged Converter/Muffler

Vehicles equipped with catalytic converter/mufflers, especially those that idle for long periods of time and/or operate in cooler climates, are susceptible to plugging. One indication of a plugged converter/muffler is poor engine response. For testing procedures of converter/mufflers, refer to the Systems Operation, Testing and Adjusting module of this Service Manual, Measurement Of Pressure In Exhaust Manifold. For information concerning the replacement of the converter/muffler refer to the Disassembly And Assembly module of this service manual.

4. Valve Adjustment Not Correct

Check and make necessary adjustments. Refer to the Systems Operation, Testing and Adjusting module of this Service Manual.

5. Turbocharger Has Carbon Deposits Or Other Cause Of Friction

Make inspection and repair turbocharger as necessary.

6. Low Gas Pressure

7. Failure Of Ignition Wires

Check for damage to wires arcing, or bare wire. Check rubber boot over spark plugs for cracks or moisture.

8. Transformer Failure

Check for loose connections, moisture, short or open circuits.

9. Faulty Spark Plugs

Check type of plug used. Install correct type. Inspect for gas leaks and/or cracked porcelain. Clean and set gap of the plugs. Install new plugs if worn.

10. Spark Plug Adapters Leak

Check for water leakage into cylinder, or combustion gases in coolant. Install new adapters.

11. Governor Actuator Linkage

Check and make necessary adjustments. Refer to the Woodward Troubleshooting Guide.

Engine Speed Is Not Stable

Probable Cause(s):

* Engine Misfiring

* Problem With Governor

* Governor Actuator Linkage

1. Engine misfiring

Refer to Engine Misfiring Or Running Rough.

2. Problem with the governor

Refer to the Woodward Troubleshooting Guide.

3. Governor Actuator Linkage

Check and make necessary adjustments. Refer to the Woodward Troubleshooting Guide.

Too Much Vibration

Probable Cause(s):

* Vibration Damper Loose

* Faulty Vibration Damper

* Engine Supports Are Loose, Incorrect Or Faulty

* Misfiring Or Running Rough

1. Vibration Damper Loose

Check vibration damper for damage. Tighten bolts. If vibration damper bolt holes have damage or wear, replace with new parts.

2. Faulty Vibration Damper

Install a new vibration damper.

3. Engine Supports Are Loose, Incorrect Or Faulty

Tighten all mounting bolts. Install new components if necessary.

4. Misfiring Or Running Rough

Refer to Engine Misfiring Or Running Rough.

Loud Combustion Noise (Sound)

Probable Cause(s):

* Low Quality Fuel

* Mechanical Problem

* Too Low Detonation

* Pre-Ignition

1. Low Quality Fuel

Test the engine with fuel according to recommendations by Caterpillar Inc.

2. Mechanical Problem

Find and correct the problem. The problem may be incorrect valve adjustment, sticking valve, or other internal problem.

3. Too Low Detonation

Refer to Detonation

4. Pre-Ignition

Refer to pre-ignition

Valve Train Noise

Probable Cause(s):

* Too Much Valve Lash

* Damage To Valve Springs, Locks, Push Tube Or Worn Valve Lifter

* Not Enough Lubrication

* Damage To Valves

* Damage To Camshaft

1. Too Much Valve Lash

Check and make necessary adjustments. Refer to the Systems Operation, Testing And Adjusting module of this Service Manual.

2. Damage To Valve Springs, Locks, Push Tube, Or Broken Or Worn Valve Lifter

Install new parts where necessary. Broken locks can cause the valve to get into the cylinder. This will cause much damage.

3. Not Enough Lubrication

Check lubrication in valve compartment. There must be a strong flow of oil at engine high rpm, but only a small flow of oil at low rpm. Oil passages must be clean, especially those that send oil to the cylinder head.

4. Damage To Valves

Make a replacement of the valves and make an adjustment as necessary.

5. Damage To Camshaft

Make a replacement of parts with damage. Clean engine thoroughly.

Oil In Cooling System

Probable Cause(s):

* Faulty Core Of Engine Oil Cooler

* Failure Of Cylinder Head Gasket

1. Faulty Core Of Engine Oil Cooler

Inspect cooler and make a replacement or repair faulty oil cooler. Flush cooling system to remove oil.

2. Failure Of Cylinder Head Gasket

Remove the radiator cap and with the engine running look for air bubbles in the coolant. Bubbles in the coolant are a sign of probable leakage at the head gasket. Remove the cylinder head from the engine. Check the cylinder head, cylinder walls and head gasket surface of the cylinder block for cracks. When installing the head, use a new head gasket. Refer to the Specification module for the proper bolt tightening sequence.

Mechanical Noise (Knock) In Engine

Probable Cause(s):

* Failure Of Bearings For Connecting Rod

* Damaged Gears

* Damaged Crankshaft

* Faulty Accessory Equipment

* Damaged Injector Rocker Arm, Missing Insert, Or Broken Socket

1. Failure Of Bearings For Connecting Rod

Inspect the bearings for the connecting rods and the bearing surfaces (journals) on the crankshaft. Install new parts where necessary.

2. Damaged Gears

Install new parts where necessary.

3. Damaged Crankshaft

Make replacement of the crankshaft.

4. Faulty Accessory Equipment

Repair as needed or install new components.

5. Damaged Injector Rocker Arm, Missing Insert, Or Broken Socket

Repair as needed or install new components.

Fuel Consumption Too High

Probable Cause(s):

* Fuel System Leaks

* Fuel And Combustion Noise (Knock)

* Wrong Ignition Timing

1. Fuel System Leaks

Check fuel system for any external leaks. Check all lines, hoses, and fittings for leaks and tighten or replace as necessary.

2. Fuel And Combustion Noise (Knock)

Refer to Misfiring And Running Rough. Refer to Loud Combustion Noise.

3. Spark Plugs Not Firing

Check spark and install new plugs if necessary.

4. Wrong Ignition Timing

Too Much Valve Lash

Probable Cause(s):

* End Of Stem Worn Or Rocker Arm Contact Surface Worn

* Worn Push Rods

* Broken Or Worn Valve Lifter

* Worn Lobes On Camshaft

* Not Enough Lubrication

1. End Of Valve Stem Worn Or Rocker Arm Contact Surface Worn

If there is too much wear, install new valves or rocker arms. Check and make necessary adjustments. Refer to the Systems Operation, Testing and Adjusting module of this Service Manual.

2. Worn Push Rods

If there is too much wear, install new valves or rocker arms. Check and make necessary adjustments. Refer to the Systems Operation, Testing and Adjusting module of this Service Manual.

3. Broken Or Worn Valve Lifter

Install new valve lifters. Check camshaft for wear. Check for free movement of valves or bent valve stem. Clean engine thoroughly. Check and make necessary adjustments. Refer to the Systems Operation, Testing and Adjusting module of this Service Manual.

4. Worn Lobes On Camshaft

Check valve lash. Check for free movement of valves or bent valve stems. Install a new camshaft. Install new valve lifters. Check and make necessary adjustments. Refer to the Systems Operation, Testing and Adjusting module of this Service Manual.

5. Not Enough Lubrication

Check lubrication in valve compartment. There must be a strong flow of oil at high engine rpm, but only a small flow at low rpm. Oil passages must be clean, especially those sending oil to the cylinder head.

Little Or No Valve Lash

Probable Cause(s):

* Worn Valve Seat Or Face Of Valve

1. Worn Valve Seat Or Face Of Valve

Reconditioning of cylinder head is needed. Check and make necessary adjustments. Refer to the Systems Operation, Testing and Adjusting module of this Service Manual.

Oil At The Exhaust

Probable Cause(s):

* Failed Turbocharger Seals

* Worn Or Failed Valve Guide Seals

* Worn Valve Guides

* Broken Or Worn Piston Rings

* Scored Or Worn Cylinder Wall(s)

1. Failed Turbocharger Seals

Check inlet manifold and exhaust manifold for oil. If oil is present, repair the turbocharger.

2. Worn Or Failed Valve Guide Seals

Inspect seals and replace as necessary.

3. Worn Valve Guides

Refer to the Specifications module for the maximum permissible wear of the valve guides. If necessary, recondition the cylinder head.

4. Broken Or Worn Piston Rings

Pistons or rings that have damage can be the cause of too much pressure in the crankcase. This condition will cause more than the normal amount of fumes (blow-by) coming from the crankcase breather. The 8T2700 Indicator Group is used to check the amount of blow-by. The test procedure is in Special Instruction, SEHS8712. Inspect and install new parts as needed.

5. Scored Or Worn Cylinder Walls

Inspect cylinder walls for problems. Hone, or bore and sleeve as necessary.

Engine Has Excessive Early Wear

Probable Cause(s):

* Dirt In Lubrication Oil

* Dirt In The Inlet Air

* Incorrect Lubrication Oil

1. Dirt In Lubrication Oil

Remove dirty lubrication oil. Install new filters. Put clean oil in the engine. Check oil filter bypass valve for a weak or broken spring.

2. Dirt In Inlet Air

Inspect all gaskets and connections. Make repairs if leaks are found.

3. Incorrect Lubrication Oil

Check oil recommendations for proper oil specifications for engine operating conditions.

Coolant In Lubrication Oil

Probable Cause(s):

* Failure Of The Oil Cooler Core

* Failure Of Cylinder Head Gasket

* Failure Of Seal Between Cylinder Head And Sleeve

* Crack Or Fault In Cylinder Head

* Crack Or Fault In Cylinder Block

1. Failure Of The Oil Cooler Core

Install a new core for the faulty oil cooler. Drain crankcase and refill with clean lubricant. Install new oil filter.

2. Failure Of Cylinder Head Gasket

3. Failure Of Seal Between Cylinder Head And Sleeve.

Replace sleeve. Apply sealant per instruction in the Specifications module of this Service Manual.

4. Crack Or Fault In Cylinder Head

Install a new cylinder head.

5. Crack Or Fault In Cylinder Block

Install a new cylinder block.

Too Much Exhaust Smoke At Normal Operating Temperatures (White, Gray, Or Blue Smoke)

White Smoke (Go to Step 1)

Probable Cause(s):

* Long Idle Periods

* Low Quality Fuel

* Valve Adjustment Not Correct

* Misfiring Cylinder(s)

* Intake/Exhaust Valves Or Piston Rings Leak Compression

Gray Smoke (Go to Step 6)

* Restrictions And Leaks In The Air Inlet System

* Exhaust System Not Open

* Faulty Turbocharger

Blue Smoke (Go to Step 9)

* Oil Level In Engine Too High

* Failure Of Turbocharger Oil Seal

* Worn Valve Guides

* Worn Piston Rings And/Or Cylinder Wall(s)

* Wear Or Damage To Pistons

1. Long Idle Periods

When an engine runs at idle speed for a long period of time, the cylinders cool and all of the fuel does not burn. Do not idle an engine for a long period of time. Stop an engine when it is not in use.

2. Low Quality Fuel

Test the engine using fuel according to recommendations by Caterpillar Inc.

3. Valve Adjustment Not Correct

Check and make necessary adjustments. Refer to the Systems Operation, Testing And Adjusting module in this Service Manual.

4. Misfiring Cylinder(s)

Refer to Engine Misfiring Or Running Rough.

5. Intake/Exhaust Valves Or Piston Rings Leak Compression

Replace worn piston rings

Gray Smoke

Probable Cause(s):

6. Restrictions And Leaks In The Air Inlet System

a. Check for leaks.

b. Check the pressure in the air inlet manifold.

c. Look for restrictions in the air cleaner.

d. Faulty air to air aftercooler. Check temperature of inlet and outlet air from air cooler. Remove any external or internal restrictions.

7. Exhaust System Not Open

Loosen the exhaust pipe from the exhaust manifold. If the engine will now start, check the exhaust system for damage and/or restrictions.

8. Faulty Turbocharger

Check inlet manifold for oil and repair turbocharger.

Blue Smoke

Probable Cause(s):

9. Oil Level In Engine Too High

Do not put too much oil in the crankcase.

10. Failure Of Turbocharger Oil Seal

Check inlet manifold for oil and repair turbocharger.

11. Worn Valve Guides

Refer to the Specifications module for the maximum permissible wear of the valve guides. If necessary, recondition the cylinder head.

12. Worn Piston Rings And/Or Cylinder Walls

Worn piston rings and/or cylinder walls can be the cause of blue smoke and can cause a loss of compression. This condition can cause more than the normal amount of fumes (blow-by) coming from the crankcase breather. The 8T2700 Indicator Group is used to check the amount of blow-by. The test procedure is in Special Instruction, SEHS8712. If necessary make a visual inspection of the cylinder walls and piston rings. Measure the cylinder walls and piston rings. For the cylinder and piston ring specifications see the Specifications module of this Service Manual. Repair and replace parts as necessary.

NOTE: High wear at low hours is normally caused by dirt coming into the engine with the inlet air.

13. Wear Or Damage To Pistons

Check piston ring to groove clearance. Pistons which have worn grooves and pistons with damage or faults can cause blue smoke and too much oil consumption. Make sure the oil return holes under the oil ring are open. Replace pistons as necessary.

Engine Has Low Oil Pressure

Probable Cause(s):

* Faulty Oil Pressure Gauge Or Sending Unit

* Dirty Oil Filter Or Oil Cooler

* Faulty Oil Pump

* Faulty Oil Pump Suction Pipe

* Oil Pressure Relief Valves Do Not Close

* Too Much Clearance Between Rocker Arm Shaft And Rocker Arms

* Too Much Clearance Between Camshaft And Camshaft Bearings

* Too Much Clearance Between Crankshaft And Crankshaft Bearings

1. Faulty Oil Pressure Gauge Or Sending Unit

Install new gauge or sending unit.

2. Dirty Oil Filter Or Oil Cooler

Change oil and oil filter. If problem persists, check the operation of bypass valve for the filter. Clean or install new oil cooler core.

3. Faulty Oil Pump

Repair or replace oil pump.

4. Faulty Oil Pump Suction Pipe

Replacement of pipe is needed.

5. Oil Pressure Relief Valve Does Not Close

Clean valve and housing. Install new parts as necessary. Check bypass valves in oil cooler and oil filter base.

6. Too Much Clearance Between Rocker Arm Shaft And Rocker Arms

Check lubrication in valve compartments. Install new parts as necessary.

7. Too Much Clearance Between Camshaft And Camshaft Bearings

Install new camshaft and camshaft bearings if necessary.

8. Too Much Clearance Between Crankshaft And Crankshaft Bearings

Inspect the bearings and make replacement as necessary.

Engine Uses Too Much Lubrication Oil

Probable Cause(s):

* Too Much Lubrication Oil In The Engine

* Oil Leaks

* Oil Temperature Is Too High

* Worn Valve Guide Seals

* Worn Pistons, Rings Or Cylinder Walls

* Failure Of Seal Rings In Turbocharger

* Worn Valve Guides

1. Too Much Lubrication Oil In Engine

Remove extra oil. Find where extra oil comes from. Put correct amount of oil in engine.

2. Oil Leaks

Find all oil leaks. Make repairs as needed. Check for a dirty crankcase breather.

3. Oil Temperature Is Too High

Check operation of oil cooler. Install new parts if necessary. Clean the core of the oil cooler.

4. Worn Valve Guide Seals

Replace as necessary.

5. Worn Pistons, Rings Or Cylinder Walls

6. Failure Of Seal Rings In Turbocharger

Check inlet manifold for oil and make repairs to the turbocharger if necessary.

7. Worn Valve Guides

Refer to the Specifications module for the maximum permissible wear of the valve guides. If necessary, recondition the cylinder head.

Coolant Temperature Above Normal

Probable Cause(s):

* Low Coolant Level

* Incorrect Mixture

* Air In Cooling System

* Fan Clutch

* Temperature Gauge

* Sending Unit

* Radiator

* Radiator Cap

* Incorrect Fan, Fan Or Shroud Not In Correct Position

* Loose Belt(s)

* Hose(s)

* Air Inlet Restriction

* Exhaust Restriction

* Shunt Line

* Water Temperature Regulator

* Faulty Water Pump

* Air Flow Through Engine Compartment

* Aftercooler

* Outside Temperature

* Operate At High Altitude

* Engine Used In Lug Condition

1. Low Coolant Level

If the coolant level is too low, not enough coolant will go through the engine and radiator. This lack of coolant will not take enough heat from the engine and there will not be enough flow of coolant to release the heat into the cooling air. Low coolant level is caused by leaks or incorrect filling of the radiator. With the engine cool, be sure that coolant can be seen at the low end of the fill neck on the radiator top tank.

2. Incorrect Mixture

Check the mixture of antifreeze and water. The mixture should be approximately 50 percent water and 50 percent antifreeze with a 3 to 6 percent coolant conditioner. If the system is not correct, drain the system as needed and put the correct mixture of water, antifreeze and coolant conditioner in the cooling system.

3. Air In Cooling System

Air can enter the cooling system in different ways. The most common causes are not filling the cooling system correctly, and combustion gas leaking into the cooling system. Combustion gas can get into the system through inside cracks, a faulty cylinder head, or head gasket. Air in the cooling system causes a reduction in coolant flow and bubbles in the coolant. Air bubbles hold coolant away from the engine parts, preventing the transfer of heat to the coolant.

4. Fan Clutch

A fan clutch not turning at the correct speed can cause improper air speed across the radiator core. The lack of proper air flow across the core can cause the coolant not to cool to the proper temperature differential.

5. Temperature Gauge

A temperature gauge which does not work correctly will not show the correct temperature. If the temperature gauge shows that the coolant temperature is too hot but other conditions are normal, either install a gauge of known accuracy, or check the cooling system with the 4C6500 Thermistor Thermometer Group.

6. Sending Unit

In some conditions the temperature sensor in the engine sends signals to a sending unit which converts these signals to an electrical impulse which is used by a mounted gauge. If for some reason the sending unit malfunctions or the electric wire breaks or shorts out the gauge can show an incorrect reading.

7. Radiator

a. Restriction to flow of coolant through core tubes of radiator of air flow restriction. Check for debris between the fins of the radiator core which prevents free air flow through the radiator core. Check the radiator for debris, dirt, or deposits on the inside of the radiator core which will prevent free flow of coolant through the radiator.

b. A radiator which is too small does not have enough area to release the heat to the cooling air. This will cause the engine to run at a higher than normal temperature. Make sure the radiator size is according to the OEMs specifications.

8. Radiator Cap

A pressure drop in the radiator can cause the boiling point to lower causing the cooling system to boil over. A cooling system pressure tester may be used to check the cooling system pressure as well as the pressure cap relief valve. If the cap fails the test, check the rubber seal on the cap as well as the operation of the pressure relief valve.

9. Incorrect Fan, Fan Or Shroud Not In Correct Position

A incorrect fan, or a fan or shroud in a wrong position will cause a reduction or a loss of air flow through the radiator. The fan must be large enough to send air through most of the area of the radiator core.

10. Loose Belt(s)

Loose fan or water pump belts will cause a reduction in air and coolant flow. Tighten the belts according to the Belt Tension Charts.

11. Hose(s)

Faulty hoses with leaks can normally be seen. Hoses that have no visual leaks can collapse (pull together) during operation and cause a restriction in the flow of coolant. Hoses become soft and/or get cracks after a period of time. The inside of a hose can deteriorate, and the loose particles of the hose can cause a restriction of the coolant flow.

12. Air Inlet Restriction

Restriction of the air coming into the engine can cause high cylinder temperatures and more than normal amount of heat to pass to the cooling system. Check for restriction with a water manometer or a vacuum gauge (which measures in inches of water). Connect the gauge to the engine air inlet between the air cleaner and the inlet to the turbocharger. With the gauge installed, run the engine at full load rpm and check the restriction. Maximum restriction of the air inlet is 6.25 kPa (25 inches of water). If the indication is higher than maximum permissible restriction, remove the foreign material from the filter element, or install a new filter element and check for the restriction again. If the indication is still too high, there must be a restriction in the inlet piping.

13. Exhaust Restriction

Restriction in the exhaust system can cause high cylinder temperatures and more than normal amount of heat to pass to the cooling system. To check if there is an exhaust restriction, make a visual inspection of the exhaust system. Check for damage to piping or for a faulty muffler. If no damage is found, check the exhaust system for back pressure from the exhaust (pressure difference measurement between exhaust outlet and atmosphere). Refer to Restriction Of Air Inlet And Exhaust in the Systems Operation, Testing And Adjusting module of this Service Manual. Check the system by removing the exhaust pipes from the exhaust manifolds. With the exhaust pipes removed, start and run the engine to see if the problem is corrected.

14. Shunt Line

A restriction of the shunt line from the radiator top tank to the engine water pump inlet, or a shunt line not installed correctly, will cause a reduction in water pump efficiency. The result will be low coolant flow and overheating.

15. Water Temperature Regulator

A water temperature regulator that does not open, or only opens part of the way, can cause above normal heating. To test the water temperature regulator refer to the Systems Operation, Testing And Adjusting module in this Service Manual.

16. Faulty Water Pump

A water pump with a loose or damaged impeller does not pump enough coolant for correct engine cooling. Remove the water pump and check for damage to the impeller. If the impeller has no damage, check the impeller clearance.

17. Air Flow Through Engine Compartment

The air flow through the radiator comes out of the engine compartment. Make sure the filters, air conditioners and similar items are not installed in a way which prevents free flow of air into and out of the engine compartment.

18. Aftercooler

Restriction of air flow through the air to air aftercooler (if equipped). Check for debris or deposits which would prevent the free flow of air through the aftercooler.

19. High Outside Temperature

When outside temperatures are too high for the rating of the cooling system, there is not enough temperature difference between the outside air and coolant temperatures.

20. Operation At High Altitude

The cooling capacity of the cooling system goes down as the engine is operated at higher altitudes. A system, under pressure, large enough to keep the coolant from boiling must be used.

21. Engine Used In A Lug Condition

"Lugging" Lugging can occur when there is too much load applied to the engine or the engine is run at a lower rpm. This low rpm causes a reduction in air flow through the radiator, and a reduction in the flow of coolant through the system. This combination of less air and less coolant flow during high input of fuel will cause above normal heating.

Coolant Temperature Below Normal

Probable Cause(s):

* Long Idle Periods

* Very Light Loads

* Water Temperature Regulator

* Air Vent Valve

* Fan Clutch Engaged

1. Long Idle Periods

When the engine is running with no load, only a small quantity of fuel is burnt and engine heat is removed too fast.

2. Very Light Load

Very light loads can cause below normal heating because of the low heat input of the engine. A slight restriction of air flow through the radiator will help to correct this problem.

3. Water Temperature Regulator

A water temperature regulator that is "stuck" open (will not move to the closed position) will cause below normal heating. A regulator that is stuck between the open and closed positions, or a vent valve that is stuck open, can cause below normal coolant temperatures when the engine has a light load.

4. Air Vent Valve

An air vent valve located in the water temperature regulator that is stuck open, can cause below normal coolant temperatures when the engine has a light load.

5. Fan Clutch Engaged

Electric fan clutch engaged. Check temperature sensor.

Exhaust Temperature Is Too High

Probable Cause(s):

* Air Inlet System Has A Leak

* Exhaust System Has A Leak

* Air Inlet Or Exhaust System Has A Restriction

* Engine Operated In A Lug Condition

* Ignition Timing

1. Air Inlet System Has A Leak

Check pressure in the air inlet manifold. Look for restriction at the air cleaner. Correct any leaks.

2. Exhaust System Has A Leak

Find cause of exhaust leak. Make repairs as necessary.

3. Air Inlet Or Exhaust System Has A Restriction

Remove restriction.

4. Engine Used In A Lug Condition

Lugging can occur when there is too much load applied to the engine or the engine is run at a lower rpm. This low rpm causes a reduction in air flow through the radiator, and a reduction in the flow of coolant through the system. This combination of less air and less coolant flow during high input of fuel will cause above normal heating.

5. Ignition Timing

Adjust ignition timing with the use of the timing light.

Starting Motor Does Not Turn

Probable Cause(s):

* Low Battery Voltage

* Faulty Cable Or Connection (Battery To Starting Motor)

* Faulty Starting Motor Solenoid

* Faulty Starting Motor

* Inside Problem Prevents Crankshaft From Turning

1. Low Or No Battery Voltage

Check battery voltage. If battery voltage is less than 8 volts for a 12 volt system, or 16 volts for a 24 volt system, put a charge on the battery. If battery will not hold a charge, load test the battery. Refer to the Systems Operation, Testing And Adjusting module in this Service Manual.

2. Faulty Switch, Wiring Or Connection In Switch Circuit

3. Faulty Starting Motor Solenoid

Remove and repair a solenoid which does not work when voltage is correct at both the battery and ignition switch connections.

4. Faulty Starting Motor

5. Inside Problem Prevents Crankshaft From Turning

Alternator Gives No Charge

Probable Cause(s):

* Loose Drive Belt For Alternator

* Faulty Charging Or Ground Return Circuit Or Battery Connections

* Faulty Brushes

* Faulty Rotor (Field Coil)

1. Loose Drive Belt For Alternator

Make an adjustment to put the correct tension on the drive belt.

2. Faulty Charging Or Ground Return Circuit Or Battery Connections

Inspect all cables and connections. Clean and tighten all connections. Make replacement of faulty parts.

3. Faulty Brushes

Install new brushes.

4. Faulty Rotor (Field Coil)

Install a new rotor.

Alternator Charge Rate Is Low Or Not Regular

Probable Cause(s):

* Loose Drive Belt For Alternator

* Faulty Charging Or Ground Return Circuit Or Battery Connections

* Faulty Alternator Regulator

* Faulty Alternator Brushes

* Faulty Rectifier Diodes

* Faulty Rotor (Field Coil)

1. Loosen Drive Belt For Alternator

Make an adjustment to put the correct tension on the drive belt.

2. Faulty Charging Or Ground Return Circuit Or Battery Connections

Inspect all cables and connections. Clean and tighten all connections. Make replacement of faulty parts.

3. Faulty Alternator Regulator

Replace the alternator regulator.

4. Faulty Alternator Brushes

Install new brushes.

5. Faulty Rectifier Diodes

Make replacement of faulty rectifier diode.

6. Faulty Rotor (Field Coil)

Install a new rotor.

Alternator Charge Too High

Probable Cause(s):

* Alternator Or Alternator Regulator Has Loose Connections

* Faulty Alternator Regulator

1. Alternator Or Alternator Regulator Has Loose Connections

Tighten all connections to alternator or alternator regulator.

2. Faulty Alternator Regulator

Replace the alternator regulator.

Alternator Has Noise

Probable Cause(s):

* Faulty Or Worn Drive Belt For Alternator

* Loose Alternator Drive Pulley

* Drive Belt And Drive Pulley For Alternator Are Not In Alignment

* Worn Alternator Bearings

1. Faulty Or Worn Drive Belt For Alternator

Install a new drive belt for the alternator.

2. Loose Alternator Drive Pulley

Check key groove in pulley for wear. If groove is worn, install a new pulley. Refer to the Specifications module in this Service Manual.

3. Drive Belt And Drive Pulley For Alternator Are Not In Alignment

Make an adjustment to put drive belt and drive pulley in correct alignment.

4. Worn Alternator Bearings

Install new bearings in the alternator.

Loss Of Coolant

Outside Leaks (Go to Step 1)

Probable Cause(s):

* Leaks In Hoses Or Connections

* Leaks In The Radiator And/Or Expansion Tank

* Leaks In The Heater

* Leaks In The Water Pump

* Cylinder Head Gasket Leakage

Coolant Leaks At The Overflow Tube (Go to Step 6)

Probable Cause(s):

* Faulty Pressure Cap

* Engine Runs Too Hot

* Expansion Tank Too Small

* Cylinder Head Gasket Leakage Or Crack(s) In Cylinder Head Or Cylinder Block

Internal Leakage (Go to Step 10)

Probable Cause(s):

* Cylinder Head Gasket Leakage

* Crack(s) In Cylinder Head

* Crack(s) In Cylinder Block

Outside Leaks

Probable Cause(s):

1. Leaks In Hoses Or Connections

Check all hoses and connections for visual signs of leakage. If no leaks are seen, look for damage to hoses or loose clamps.

2. Leaks In The Radiator And/Or Expansion Tank

Put pressure to the radiator and/or expansion tank with the 9S8140 Cooling System Pressurizing Pump Group and check for leaks.

3. Leaks In The Heater

Put pressure to the cooling system with the 9S8140 Cooling System pressurizing Pump Group and check for leaks.

4. Leaks In The Water Pump

Check the water pump for leaks before starting the engine, then start the engine and look for leaks. If there are leaks at the water pump, repair or install a new water pump.

5. Cylinder Head Gasket Leakage

Look for leaks along the surface of the cylinder head gasket. If you see leaks, install a new head gasket. Refer to the Specifications module for the proper bolt tightening sequence.

Coolant Leaks At The Overflow Tube

Probable Cause(s):

6. Faulty Pressure Cap

Check the sealing surfaces of the pressure cap and the radiator to be sure the cap is sealing correctly. Check the opening pressure and sealing ability of the pressure cap valve with the 9S8140 Cooling System Pressurizing Pump Group.

7. Engine Runs Too Hot

If coolant temperature is too high, pressure will be high enough to move the cap off of the sealing surface in the radiator and cause coolant loss through the overflow tube. Refer to Above Normal Coolant Temperature.

8. Expansion Tank Too Small

The expansion tank can be either a part of the radiator or it can be installed separately from the radiator. The expansion tank must be large enough to hold the expansion of the coolant as it gets warm or has sudden changes in pressure. Make sure the expansion tank is installed correctly, and the size is according to the recommendations of the OEM.

9. Cylinder Head Gasket Leakage, Or Crack(s) In Cylinder Head Or Cylinder Block

Remove the radiator cap and with the engine running look for air bubbles in the coolant. Bubbles in the coolant are a sign of probable leakage at the head gasket. Refer to LEVN2245, "Detection Of Air And Combustion Gases In The Cooling System" for more information. Remove the cylinder head from the engine. Check the cylinder head, cylinder walls and head gasket surface of the cylinder block for cracks. When installing the head, use a new head gasket. Refer to the Specifications module for the proper bolt tightening sequence.

Internal Leakage

Probable Cause(s):

10. Cylinder Head Gasket Leakage

If the cylinder head gasket leaks between a water passage and an opening into the crankcase, coolant will get into the crankcase.

11. Crack(s) In Cylinder Head

Crack(s) in the upper surface of the cylinder head, or an area between a water passage and an opening into the crankcase, can allow coolant to get into the crankcase.

12. Crack(s) In Cylinder Block

Crack(s) in the cylinder block between a water passage and the crankcase will let coolant get into the crankcase.

Short Spark Plug Life

Probable Cause(s):

* Wrong Polarity Of Connections At Transformers

* Wrong Spark Plugs

1. Wrong Polarity Of Connections At Transformers

Check the wiring diagrams in this manual. Make changes to the connection of wires to the primary coil of transformers.

2. Wrong Spark Plugs

Install the correct spark plugs

Pre-Ignition

Probable Cause(s):

* Worn Spark Plugs

* Water Leakage In Cylinder Or Combustion Gas

1. Worn Spark Plugs

Clean and make adjustment to the plug gap. If worn install new plugs

2. Water Leakage In Cylinder Or Combustion Gas

Inspect spark plug adapter gasket. Check spot face for adapter in head for roughness. Install a new adapter to correct torque.

Detonation

Probable Cause(s):

* Deposits In Combustion Chamber

* High Ambient Air Temperature

* Engine Used In Lug Condition

* Aftercooler

* FARC Too "Rich"

1. Deposits In Combustion Chamber

Remove deposits from combustion chamber.

2. Check for high engine room temperature or high temperature of water to aftercooler.

3. Engine Used In Lug Condition

4. Aftercooler

Restriction of air flow through the air to air aftercooler (if equipped). Check for debris or deposits which would prevent the free flow of air through the aftercooler.

5. FARC Too "Rich"

Check and make adjustment to gas regulator setting.

Gas Supply Line Shutoff Valve Failure

Probable Cause(s):

* Defect In Solenoid

* Wrong Electrical Rated Solenoid

* Defect In Wiring And/Or Connections

1. Defect In Solenoid

Install New Solenoid.

2. Wrong Electrical Rated Solenoid

Install new solenoid valve with correct valve.

3. Defect In Wiring And/Or Connections

Correct the defect in wiring and connections.

Fuel System

Start Up Procedure

For proper starting procedure, refer to G3306 Truck Engine Operation And Maintenance Manual.

Use this procedure when an engine is started for the first time after work is done on the fuel system

1. Disconnect the air inlet system from the turbocharger. Use this procedure when an engine is started for the first time after work is done on the fuel system

2. Have a person in position near the turbocharger air inlet with a piece of steel plate large enough to completely cover the turbocharger air inlet.

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Be careful when plate is put against air inlet opening. Due to excessive suction, the plate can be pulled quickly against air inlet opening. To avoid crushed fingers, do not put fingers between plate and air inlet opening.

3. Start the engine. If the engine starts to run too fast or runs out of control, immediately put the steel plate against the turbocharger air inlet. This will stop the air supply to the engine, and the engine will stop.

Locating Top Center Compression Position For No. 1 Piston

No. 1 piston at top center (TC) on the compression stroke is the starting point for all timing procedures.

NOTE: The engine is seen from the flywheel end when direction of crankshaft rotation is given.

1. Remove starting motor.

2. Install the tools as shown.

Engine Turning Tools Installed
(1) 5P7306 Housing. (2) 5P7305 Gear. (3) Timing bolt.

3. Remove the valve cover.

4. Rotate the crankshaft clockwise approximately 30 degrees. The reason for this step is to be sure the free play is removed from the timing gears when the engine is put on top center.

5. Remove the plug from the timing hole in the flywheel housing. Rotate the crankshaft until a 3/8-16 NC bolt, 50.8 mm (2.00 in) long, can be turned into the flywheel through the timing hole in the flywheel housing. No. 1 piston is now on top center.

NOTE: If the crankshaft is turned beyond top center do Steps 4 and 5 again.

6. The intake and exhaust valves for No. 1 cylinder will be closed if No. 1 piston is on the compression stroke. You can move the rocker arms up and down with your hand.

7. If No. 1 piston is not on the compression stroke, remove the timing bolt and rotate the crankshaft counterclockwise 360 degrees. Install the timing bolt. The No. 1 piston is now at top center on the compression stroke.

Spark Plugs And Adapters

If the spark plug rubber boot is not covering the top of the spark plug wires then water leakage or detonation and pre-ignition can be the result. Adapters are installed and removed with an 8S7227 Wrench and 8H8538 Socket.

(1) Adapter. (2) 9.5250 mm (3/8 inch) Drive extension. (3) Spark plug. (4) 8H8538 Spark plug socket.

Voltage to cause the spark will change with the spark plug condition and engine load. A new spark plug in an engine at low idle will take 3000 to 6000 volts. At full load, this voltage will be 8000 to 10000 volts. When the gap of the spark plug needs adjustment the voltage needed will be over 10000 volts. Voltage needed will go higher if a plug gap adjustment is not made. Spark plugs start to cause the engine to run rough (fire erratically) when the spark plug voltage needs to go higher than 10000 volts.

Spark plug gap must be kept at 0.36 ± 0.03 mm (0.014 ± 0.001 in). The use of 9U6695 Firing Indicator is an aid for finding ignition problems. Follow the instructions that come with the tool.

Put liquid soap on the seat groove of adapter (1) and seal. Install the adapter into cylinder head and tighten to a torque of 95 ± 7 N·m (70 ± 5 lb ft). Spark plugs (3) must be installed to a torque of 36 ± 5 N·m (26 ± 4 lb ft) with 8H8538 Spark Plug Socket (4).

Adjusting Engine Timing

Right Side View.
(1) Magnetic pick-up sensor. (2) Timing drive group cover. (3) Timing drive group housing.

1. Put No. 1 piston at top center on the compression stroke. Make reference to Locating Top Center Compression Position For No. 1 Piston.

2. Remove magnetic pick-up sensor (1) from the side of the timing drive group housing (3).

3. Remove the timing drive cover (2) from the front of the timing drive group housing (3).

Front View.
(4) Magnetic pick-up locations. (5) Timing disc. (6) Bolt. (7) Indexed magnet.

4. Locate the indexed magnet (7) by visually finding the magnet that corresponds with a "X" on the timing disc. Another method is to locate the two magnets that are approximately 10 degrees apart on the timing disc (5). The indexed magnet will be the next clockwise magnet on the timing disc (5).

5. Loosen bolt (6) that holds the timing disc (5) to the timing gear.

6. Rotate the timing disc (5) until the indexed magnet (7) is located before the magnetic pick-up sensor (1). Refer to the following chart for your application.

7. Tighten the timing disc bolt (6) to 47 ± 9 N·m (34.6 ± 6.6 lb ft).

8. Tighten the bolts that hold the timing drive group cover (2) to the timing drive group housing (3) to 12 ± 3 N·m (9 ± 2.2 lb ft).

9. Install the magnetic pick-up sensor (1) in the threaded hole. Back the magnetic pick-up sensor out 3/4 turn from the timing disc (5) surface. Tighten the locknut to 45 ± 7 N·m (33 ± 5 lb ft).

Crankshaft Positions For Valve Lash Setting

G3306 Truck Engine Cylinder And Valve Location

Engine Speed Measurement

9U7400 Multitach Group

The 9U7400 Multitach Group can measure engine speed from a magnetic pickup on the flywheel housing. It also has the ability to measure engine speed from visual engine parts in rotation.

Special Instruction, SEHS7807 is with the 9U7400 Multitach Group and gives instructions for the test procedure.

The 1U6602 Tachometer Group is a phototach for general use. The 1U6602 Tachometer Group is a phototach only and reads only the basic input frequency (1 pulse per revolution per piece of reflective tape) on any visible rotating part. The 1U6602 Tachometer Group does not replace the 9U7400 Multitach Group.

Special Instruction, SEHS8854 is with the 1U6602 Tachometer Group and gives instructions for its use.

Air Inlet And Exhaust System

Restriction Of Air Inlet And Exhaust

There will be a reduction of horsepower and efficiency of the engine if there is a restriction in the air inlet or exhaust system.

Air flow through the air cleaner must not have a restriction (negative pressure difference measurement between atmospheric air and air that has gone through air cleaner) of more than 3.75 kPa (15 inches of water).

Back pressure from the exhaust (pressure difference measurement between exhaust at outlet elbow and atmospheric air) must not be more than 6.75 kPa (27 inches of water).

Measurement Of Pressure In Inlet Manifold

The efficiency of an engine can be checked by making a comparison of the pressure in the inlet manifold with the specifications given in the TMI (Technical Marketing Information). This test is used when there is a decrease of horsepower from the engine, yet there is no real sign of a problem with the engine. Development of this information is done with these conditions:

* 100 kPa (29 inches of Hg) barometric pressure (dry).

* 29°C (85°F) outside air temperature.

Any change from these conditions can change the pressure in the inlet manifold. Outside air that has higher temperature and lower barometric pressure than given above will cause a lower horsepower and a lower inlet manifold pressure measurement than given in the TMI. Outside air that has a lower temperature and a higher barometric pressure will cause higher horsepower and a higher inlet manifold pressure measurement.

NOTE: Be sure that the air inlet or exhaust does not have a restriction when making a check of pressure in the inlet manifold.

1U5470 Engine Pressure Group

Pressure Test Location
(1) Plug.

To check the inlet manifold pressure, remove one of the plugs (1) on top of inlet manifold. Connect the adapter, seal, reducing bushing, and 1U5470 Engine Pressure Group to this opening.

The 1U5470 Engine Pressure Group has a gauge to read pressure in the inlet manifold. Special Instruction, SEHS8524, is with the tool group and gives instruction for its use.

Exhaust Temperature

Use the 123-6700 Infrared Thermometer to check exhaust temperature. The Operator's Manual, NEHS0510, for the 123-6700 Infrared Thermometer gives complete operating and maintenance instructions for this tool. Take temperature readings soon after the engine is installed. Regular checks are needed, and a record kept, to find any large increase or decrease in exhaust temperature.

Exhaust temperatures will not be the same for all engines of a similar type. Factors that have an affect on the exhaust temperatures are:

* Restriction in the air inlet system

* Restriction in the exhaust system

* Temperature of the inlet air

* Friction inside the engine

* Fuel rate, fuel system condition or setting

* Height of engine above sea level (altitude)

* Size of valve openings

* Condition of infrared thermometer

* Location of thermocouple

Checking the exhaust temperature, by itself, is not a complete method of making an analysis of an engine problem. A large or sudden temperature change will give an indication that something is wrong in the engine. Other checks must be made to find the cause.

Air-to-Air Aftercooled Systems

Visual Inspection

Inspect all air lines, hoses and gasket connections at each oil change. Make sure the constant torque hose clamps are tightened to the correct torque. Check the truck manufacturer's specifications for the correct torque. Check welded joints for cracks and make sure all brackets are tightened in position and are in good condition. Use compressed air to clean cooler core blockage caused by debris or dust. Inspect the cooler core fins for damage, debris or salt corrosion. Use a stainless steel brush with soap and water to remove corrosion.

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Pressure air can cause personal injury.

When using pressure air for cleaning, wear a protective face shield, protective clothing and protective shoes.

NOTE: When air-to-air aftercooler system parts are repaired and/or replaced, a leak test is recommended.

The use of winter fronts or shutters is discouraged with air-to-air aftercooled systems. Winter fronts can only be used on truck models where tests have shown that the engine jacket water will overheat before the inlet manifold air temperature is excessive. On these trucks, sensors and gauges or alarms are installed to indicate engine operating conditions before excessive inlet manifold air temperatures are reached. Check with the truck manufacturer on winter front and shutter application.

Air System Restriction

Pressure measurements should be taken at the turbocharger outlet and at the inlet manifold. When the total pressure drop of the charged air system at maximum air flow exceeds 13.5 kPa (4 inches of Hg), the air lines and cooler core must be inspected for internal restriction and cleaned, repaired or replaced as necessary.

Turbocharger Failure

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Pressure air can cause personal injury.
When using pressure air for cleaning, wear a protective face shield, protective clothing and protective shoes.

The maximum air pressure must be below 205 kPa (30 psi) for cleaning purposes.

If a turbocharger failure occurs, remove the air-to-air cooler core and flush internally with a solvent that removes oil and other foreign substances. Shake cooler to eliminate any trapped debris. Wash with hot, soapy water; rinse thoroughly with clean water; and blow dry with compressed air in reverse direction of normal air flow. Carefully inspect the system to make sure it is clean.

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NOTICE

Do not use caustic cleaners or damage to the aftercooler core will result.

Inlet Manifold Pressure

Normal inlet manifold pressure with high exhaust temperature can be caused by cooler core fin blockage. Clean the cooler core fins, see Visual Inspection for the cleaning procedure to use.

Low inlet manifold pressure and high exhaust manifold temperature can be caused by any of the conditions that follow:

1. A plugged air cleaner. Clean or replace the air cleaner as needed.

2. A blockage in the air lines between the air cleaner and turbocharger. All restrictions must be removed.

3. Cooler core leakage. Pressure test the cooler core, see Aftercooler Core Leakage for the correct procedure to use and repair or replace parts as needed.

4. Leakage from the pressure side of the induction system. Check and repair leaks.

5. Inlet manifold leak. Check for loose, missing and damaged fittings or plugs. Also check the manifold to cylinder head gaskets.

Aftercooler Core Leakage

Using FT1984 Air-to-Air Aftercooler Test Group
(1) Regulator and valve assembly. (2) Nipple. (3) Relief valve. (4) Tee. (5) Coupler. (6) Aftercooler. (7) Dust plug. (8) Dust plug. (9) Chain.

A low power problem in the engine can be the result of aftercooler leakage. Low power, low boost pressure, black smoke, and/or high exhaust temperature can be the result of an aftercooler system leakage.

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NOTICE

Remove all air leaks from the system to prevent engine damage. In some operating conditions, the engine can pull a manifold vacuum for short periods of time. A leak in the aftercooler or air lines can let dirt and other foreign material into the engine and cause rapid wear and/or damage to engine parts.

A large cooler core leak often can be found by making a visual inspection. To check for smaller leaks, use the following procedure:

1. Disconnect the air pipes from the inlet and outlet side of the aftercooler core.

2. Install couplers (5) and dust plugs (7) & (8) from the FT1984 Air-to-Air Aftercooler Test Group as shown on each side of the aftercooler core. Installation of additional hose clamps on hump hoses is recommended to prevent the hoses from bulging while the aftercooler core is being pressurized.

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Dust plug chains (9) must be installed to the aftercooler core or the radiator brackets to prevent possible injury while testing. Do not stand in front of the dust plugs while testing.

3. Install regulator and valve assembly (1) on the outlet side of the aftercooler. Attach air supply.

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NOTICE

Do not use more than 240 kPa (35 psi) air pressure or damage to the aftercooler core can be the result.

4. Open air valve and pressurize the aftercooler to 205 kPa (30 psi). Shut off air supply.

5. Inspect all connections for air leakage.

6. System pressure should not drop more than 35 kPa (5 psi) in 15 seconds.

7. If the pressure drop is more than specified, use a solution of soap and water to check all areas of possible leakage and look for air bubbles. Replace hoses or repair the aftercooler core as needed.

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To help prevent personal injury when the tooling is removed, relieve all pressure in the system slowly by using air regulator and valve assembly (1).

8. After testing, remove FT Tooling and connect air pipes on each side of the aftercooler.

Dynamometer Test

Air-to-air aftercooled chassis dynamometer tests, in hot ambient temperatures, can add a greater heat load to the jacket water cooling system, therefore the jacket water cooling system temperature must be monitored. Also, monitor the inlet air temperature as it may need a power correction factor.

For engine dynamometer tests, use the FT1438 Dynamometer Testing Aftercooler. FT1438 provides an air to water aftercooler to control the inlet air temperature to 43°C (110°F).

Engine Blow-By (Air Flow)

Crankcase blowby and cylinder pressure, as well as oil analysis, provide good management feedback as to the condition of spark ignited engines. These preventive maintenance checks can be used to monitor valve and ring condition.

Because the American Petroleum Institute (API) does not have lube oil performance classifications for spark ignited engine oil (NGEO), there is always the potential for a lube oil problem. A common result of an oil problem is a stuck piston ring. A stuck ring(s) will raise cylinder blowby which deteriorates the oil quickly.

When this condition is identified by oil analysis and blowby measurement, the engine should be immediately scheduled for inspection. The piston with the stuck ring(s) should be repaired or replaced. The cylinder pressure reading can help identify the cylinder with the stuck ring(s). Refer to the following chart for typical cylinder pressures.

Cylinder Pressure Chart

Exhaust Valve Wear

Base line exhaust valve projection measurements should be taken at initial engine start-up. Monitor valve take-up on a schedule based on valve wear rate as defined by the following chart to determine the optimum Top End Overhaul.

Measurement Interval Versus Valve Stem Height Chart

Measure and record each valve stem projection above the top deck of the cylinder head. The valve take-up should then be monitored per the chart until the take-up is 70 percent of the 2.3 mm (.090 in) limit. After reaching 70 percent of the limit, valve take-up measurements are to be made every month until overhaul.

When valve adjustment take-up totals 70 percent of the limit [1.6 mm (.063 in)], cylinder head maintenance should be scheduled and work should be completed before the measurement reaches 100 percent of the limit, 2.3 mm (.090 in).

Refer to/use the EXHAUST VALVE DATA SHEET on the following page to record exhaust wear, crankcase blowby and cylinder pressure. The leakage method to determine cylinder condition is still the preferred method.

Compression is given because it is common in the industry and can easily be measured during spark plug inspection.

The engine blowby is measured with the Caterpillar 8T2700 blowby/air flow indicator. Refer to Special Instruction, SEHS8712, provided with the tool.

Cylinder Head

The cylinder head has valve seat inserts, valve guides and brass sleeves that can be removed when they are worn or have damage. Replacement of these components can be made with available service tool groups that are referred to in the Disassembly And Assembly.

Valve Lash

Valve lash is measured between the rocker arm and the valve. All lash measurements and adjustments must be made with the engine stopped, and with the valves FULLY CLOSED.

Valve Lash Check

When the valve lash is checked, adjustment is NOT NECESSARY if the measurement is in the range given in the chart VALVE LASH CHECK: ENGINE STOPPED. If the measurement is outside this range, adjustment is necessary. See the chart for VALVE LASH SETTING: ENGINE STOPPED, and make the setting to the nominal (desired) specifications in this chart. Refer to Operation And Maintenance Manual for service interval for valve lash adjustment.

NOTE: For valve lash specifications and measurement procedure refer to Fuel System; Crankshaft Positions For Valve Lash Setting, located in this manual.

G3306 Truck Engine Cylinder And Valve Location

Valve Lash Adjustment

Use the procedure that follows for adjustment of the valves:

1. Put No. 1 piston at top center (TC) position. Make reference to Finding Top Center Position For No. 1 Piston.

2. With No. 1 piston at top center position of the correct stroke, adjustment can be made to the valves as shown in the chart CRANKSHAFT POSITIONS FOR VALVE LASH SETTING in this manual.

NOTE: Before any actual adjustments are made, tap (hit lightly) each rocker arm (at top of adjustment screw) with a soft mallet to be sure that the lifter roller is seated against the camshaft base circle.

Valve Lash Adjustment
(1) Valve. (2) Rocker arm. (3) Locknut. (4) Adjustment screw.

3. Loosen the locknut (3) for the push rod adjustment screw. If there is not enough clearance for feeler gauge between rocker arm (2) and valve (1), turn the adjustment screw (4) counterclockwise to increase the valve lash.

4. Put a feeler gauge of the correct dimension between the rocker arm and valve. Turn the adjustment screw clockwise until the valve lash is set to the specifications in the chart VALVE LASH SETTING: ENGINE STOPPED.

5. After each adjustment, tighten locknut (3) to a torque of 25 ± 7 N·m (18 ± 5 lb ft) and check the adjustment again.

6. Remove the top center (TC) bolt and turn the flywheel 360 degrees in the direction of engine rotation. This will put No. 1 piston at top center (TC) position on the opposite stroke. Install the top center (TC) bolt in the flywheel.

7. With No. 1 piston at top center position on the opposite stroke, adjustment can be made to the remainder of the valves as shown in the chart CRANKSHAFT POSITIONS FOR VALVE LASH SETTING.

8. Repeat Steps 3, 4 and 5 for these valve adjustments.

9. Remove the top center (TC) bolt from the flywheel when all valve lashes have been adjusted.

Turbocharger

The turbocharger senses boost pressure which actuates the wastegate valve which will control the amount of exhaust gas that will be allowed to bypass the turbine side of the turbocharger. The speed of the turbocharger is controlled by the wastegate valve.

(1) Actuating rod. (2) Canister. (3) Line.

When the engine is operating under low boost (lug) conditions a spring pushes against a diaphragm in canister (2) and moves actuating rod (1) to close the wastegate valve which will allow the turbocharger to operate at maximum performance.

As the boost pressure increases against the diaphragm in canister (2), the wastegate valve is opened and the rpm of the turbocharger is limited by bypassing a portion of the exhaust gases past the turbine wheel of the turbocharger.

An indication of a problem with the wastegate turbocharger is:

* boost pressure is too high at full load conditions.

* boost pressure is too low at all lug conditions.

The correct pressure for the inlet manifold is given in TMI (Technical Marketing Information).

To check the operation of the wastegate valve, verify the correct Wastegate Check Pressure by referencing the letter code stamped on the wastegate lever arm to the corresponding pressure. Remove the air line and slowly apply the check pressure to the canister. DO NOT EXCEED 200 kPa (29 psi).

The actuating lever should move 0.50 ± 0.25 mm (0.020 ± 0.010 in) when the external supply of air connected to the line reaches the corresponding wastegate check pressure. If the actuating lever does not move 0.50 mm (0.020 in) replace the turbine housing assembly (which includes the wastegate) or the complete turbocharger.

To check the operation of the wastegate valve, remove line (3) and slowly apply 200 kPa (29 psi) of air to canister (2). DO NOT EXCEED 200 kPa (29 psi). The actuating lever should move more than .50 mm (.020 in) when the external supply of air is connected to line (3). If the actuating lever does not move at least .50 mm (.020 in), replace the turbine housing assembly (includes wastegate), or the complete turbocharger.

NOTE: The wastegate turbine housing assembly is preset at the factory and no adjustments can be made.

Maximum rpm of the turbocharger is controlled by the boost pressure (which controls the position of the wastegate valve), the engine rating, the high idle rpm setting and the height above sea level at which the engine is operated.

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NOTICE

If the high idle rpm or the engine rating is higher than given in TMI (Technical Marketing Information) for the height above sea level at which the engine is operated, there can be damage to engine or turbocharger parts. Damage will result when increased heat and/or friction due to the higher engine output goes beyond the engine cooling and lubrication systems abilities.

Gas Line Pressure

Gas engines burn a wide range of gaseous fuels. BTU rating of a fuel is a measure of the power content of the fuel. The higher BTU rated fuels need less gas pressure to have the correct gas volume for a specific horsepower.

The BTU HHV (high heat value) of gaseous fuels is the unit of measurement of the total fuel heat content. The BTU LHV (low heat value) content is more important. The combustion procedure in a cylinder causes carbon dioxide and water, but the heat needed for the conversion of water to vapor is lost and can not be used in the engine. The remainder of the heat that can be used from the fuel is the LHV, and, as a rule, is 10 percent less than the HHV of natural gas. When BTU HHV is given, remember to make a conversion to LHV so the correct settings can be made.

Low octane fuels burn so fast that an adjustment to the timing must be made to move it back (retard). With early timing and low octane fuel, the fast burning fuel burns too much before the piston goes over top center. The result of this is "knocking" (detonation).

A change to the fuel to air ratio is made by changing the gas pressure in relation to the air pressure. Too much gas makes a "rich mixture" and not enough gas makes a "lean mixture". Either will cause a loss of power. If the compression is too high and the fuel to air mixture is too rich, fuel ignition will be without the aid of the spark and at a time different than the timing setting. When propane gas is used, the adjustment of the fuel to air setting must be made with much more precision than when natural gas is used.

Make an adjustment to (regulate) the pressure in main gas supply to the engine. The gas supply line pressure for compressed natural gas should be 1100 to 1240 kPa (160 to 180 psi). The gas supply line pressure for liquid propane gas should be a minimum of 138 kpa (20 psi).

Lubrication System

One of the problems in the list that follows will generally be an indication of a problem in the lubrication system for the engine.

* Too Much Oil Consumption

* Oil Pressure Is Low

* Oil Pressure Is High

* Too Much Bearing Wear

* Increased Oil Temperature

Too Much Oil Consumption

Oil Leakage On Outside Of Engine

Check for leakage at the seals at each end of the crankshaft. Look for leakage at the oil pan gasket and all lubrication system connections. Check to see if oil comes out of the crankcase breather. This can be caused by combustion gas leakage around the pistons. A dirty crankcase breather will cause high pressure in the crankcase, and this will cause gasket and seal leakage. Check for leakage at the seals at each end of the high pressure oil line. Look for leakage at the high pressure pump.

Oil Leakage Into Combustion Area Of Cylinders

Oil leakage into the combustion area of the cylinders can be the cause of blue smoke. There are four possible ways for oil leakage into the combustion area of the cylinders:

* Oil leakage between worn valve guides and valve stems.

* Worn or damaged piston rings, or dirty oil return holes in the piston.

* Worn or damaged and/or intermediate ring not installed correctly.

* Oil leakage past the seal ring in the impeller end of the turbocharger shaft.

* Oil level too high due to error in filling, mis-marked, or incorrect dip stick.

Too much oil consumption can also be the result if oil with the wrong viscosity is used. Oil with a thin viscosity can be caused by fuel leakage into the crankcase, or by increased engine temperature and results in too much oil consumption.

Measuring Engine Oil Pressure

An oil pressure gauge that has a defect can give an indication of low or high oil pressure

1U5470 Engine Pressure Group

The 1U5470 Engine Pressure Group can be used to measure the pressure in the system. This tool group has a gauge to read pressure in the oil manifold. Special Instruction, SEHS8524 is with the tool group and gives instructions for its use.

Oil Gallery Plug
(1) Plug.

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Work carefully around an engine that is running. Engine parts that are hot, or parts that are moving, can cause personal injury.

Oil pressure to the camshaft and main bearings should be checked on the side of the cylinder block at oil gallery plug (1). Install the adapter, seal, reducing bushing, and the 1U5470 Engine Pressure Group to this opening. With the engine at operating temperature (using SAE 10W30 oil), under full load condition, minimum oil pressure should be 250 kPa (36 psi). With the engine at operating temperature (using SAE 10W30 oil), at 750 to 850 rpm low idle, minimum oil pressure is 100 kPa (15 psi). With the engine at operating temperature (using SAE 10W30 oil), under full load condition, maximum oil pressure is 600 kPa (88 psi).

Engine Oil Pressure Graph

Oil Pressure Is Low

Crankcase Oil Level

Check the level of the oil in the crankcase. Add oil if needed. It is possible for the oil level to be too far below the oil pump supply tube. This will cause the oil pump not to have the ability to supply enough lubrication to the engine components, or to supply enough oil to the high pressure hydraulic pump for proper operation of the unit injectors..

Oil Pump Does Not Work Correctly

The inlet screen of the supply tube for the oil pump can have a restriction. This will cause cavitation (low pressure bubbles suddenly made in liquids by mechanical forces) and a loss of oil pressure. Air leakage in the supply side of the oil pump will also cause cavitation and loss of oil pressure. If the bypass valve for the oil pump is held in the open (unseated) position, the lubrication system cannot get to maximum pressure. Oil pump gears that have too much wear will cause a reduction in oil pressure.

Oil Filter Bypass Valve

If the bypass valve for the oil filter is held in the open position (unseated) because the oil filter has a restriction, a reduction in oil pressure can result. To correct this problem, remove and clean the bypass valve and bypass valve bore. Install a new Caterpillar oil filter to be sure that no more debris makes the bypass valve stay open.

Too Much Clearance At Engine Bearings Or Open Lubrication System (Broken Or Disconnected Oil Line Or Passage)

Components that are worn and have too much bearing clearance can cause oil pressure to be low. Low oil pressure can also be caused by an oil line or oil passage that is open, broken or disconnected.

Piston Cooling Jet Tube

More than one type cooling jet is in use, and they are not interchangeable. Follow the engine arrangement to be sure that correct parts are being installed.

When the engine is operated, cooling jets direct oil toward the bottom of the piston to cool the piston and also provide lubrication for the piston pin. If a cooling jet is broken, plugged or installed wrong, seizure of the piston will be caused in a very short time.

Oil Pressure Is High

Oil pressure will be high if the bypass valve for the oil pump cannot move from the closed position.

Too Much Bearing Wear

When some components of the engine show bearing wear in a short time, the cause can be a restriction in an oil passage.

If the gauge for oil pressure shows enough oil pressure, but a component is worn because it cannot get enough lubrication, look at the passage for oil supply to the component. A restriction in a supply passage will not let enough lubrication get to a component, and this will cause early wear.

Increased Oil Temperature

With the engine at operating temperature (using SAE 10W30 oil), the maximum oil temperature is 115°C (239°F)

Look for a restriction in the oil passages of the oil cooler. If the oil cooler has a restriction, the oil temperature will be higher than normal when the engine is operated. A restriction only in the oil cooler will not cause the engine oil pressure to be at a low level.

Also check the oil cooler bypass valve to see if it is held in the open position (unseated). This condition will let the oil through the valve instead of the oil cooler, and oil temperature will increase.

Gauges For Oil Pressure

An oil pressure gauge or a sender that has a defect can give an indication of low or high oil pressure.

The 1U5470 Engine Pressure Group can be used to make a comparison with instrument panel gauges.

The 1U5470 Engine Pressure Group can be used to measure the pressure in the system. This tool group has a gauge to read pressure in the oil manifold. Special Instruction, SEHS8907 is with the tool group and gives instructions for its use.

Cooling System

These engines have a pressure type cooling system. A pressure type cooling system gives two advantages. The first advantage is that the cooling system can have safe operation at a temperature that is higher than the normal boiling (steam) point of water. The second advantage is that this type system prevents cavitation (low pressure bubbles suddenly made in liquids by mechanical forces) in the water pump. With this type system, it is more difficult for an air or steam pocket to be made in the cooling system.

The cause for increased engine temperature is generally because regular inspections of the cooling system were not made. Make a visual inspection of the cooling system before a test is made with test equipment.

Visual Inspection Of The Cooling System

1. Check coolant level in the cooling system.

2. Look for leaks in the system.

3. Look for bent radiator fins. Be sure that air flow through the radiator does not have a restriction.

4. Inspect the drive belts for the fan.

5. Check for damage to the fan blades.

6. Look for air or combustion gas in the cooling system.

7. Inspect the filler cap and the surface that seals the cap. This surface must be clean.

Testing The Cooling System

Remember that temperature and pressure work together. When a diagnosis is made of a cooling system problem, temperature and pressure must both be checked. Cooling system pressure will have an effect on coolant boiling temperatures. For an example, look at the chart to see the effect of pressure and height above sea level on the boiling (steam) point of water.

Test Tools For Cooling System

4C6500 Thermistor Thermometer Group

The 4C6500 Thermistor Thermometer Group is used in the diagnosis of overheating (engine hotter than normal) or over cooling (engine cooler than normal) problems. This group can be used to check temperatures in several different parts of the cooling system. The testing procedure is in Special Instruction, SEHS8446.

8T2700 Blow-by/Air Flow Indicator Group

8T2700 Indicator Group

The 8T2700 Blow-by/Air Flow Indicator Group is used to check the air flow through the radiator core. The test procedure is in Special Instruction, SEHS8712.

9U7400 Multitach Group or 1U6602 Tachometer Group (Photo-Tachometer)

9U7400 Multitach Group

The 9U7400 Multitach Group is used to check the fan speed. The testing procedure is in Special Instruction, SEHS7807.

The 9U7400 Multitach Group can measure engine speed from a magnetic pickup on the flywheel housing. It also has the ability to measure engine speed from visual engine parts in rotation.

Special Instruction, SEHS7807 is with the 9U7400 Multitach Group and gives instructions for the test procedure.

1U6602 Tachometer Group (Photo-Tachometer)

The 1U6602 Tachometer Group is a hand held phototach for general use. The 1U6602 Tachometer Group is a phototach only and reads only the basic input frequency (one pulse per revolution per piece of reflective tape) on any visible rotating part. The 1U6602 Tachometer Group does not replace the 9U7400 Multitach Group.

Special Instruction, SEHS8854 is with the 1U6602 Tachometer Group and gives instructions for its use.

9S8140 Cooling System Pressurizing Pump Group

The 9S8140 Cooling System Pressurizing Pump Group is used to test pressure caps and to pressure check the cooling system for leaks.

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DO NOT loosen the filler or pressure cap on a hot engine. Steam or hot coolant can cause severe burns.

Checking Pressure Cap

One cause for a pressure loss in the cooling system can be a defective seal on the radiator pressure cap.

Typical Schematic Of Pressure Cap
(A) Sealing surface of cap and radiator.

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DO NOT loosen the filler or pressure cap on a hot engine. Steam or hot coolant can cause severe burns.

After the engine is cool, loosen the pressure cap and let the pressure out of the cooling system. Then remove the pressure cap.

Inspect the pressure cap carefully. Look for damage to the seal or to the surface that seals. Any foreign material or deposits on the cap, seal or surface that seals, must be removed.

9S8140 Cooling System Pressurizing Pump Group

The 9S8140 Cooling System Pressurizing Pump Group is used to test pressure caps and to pressure check the cooling system for leaks.

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DO NOT loosen the filler or pressure cap on a hot engine. Steam or hot coolant can cause severe burns.

To check the pressure cap for the pressure that makes the pressure cap open, use the procedure that follows:

1. Remove the pressure cap from the radiator.

2. Put the pressure cap on the 9S8140 Cooling System Pressurizing Pump Group.

3. Look at the gauge for the exact pressure that makes the pressure cap open.

4. Make a comparison of the reading on the gauge with the correct pressure at which the pressure cap must open.

5. If the pressure cap is defective, install a new pressure cap.

Testing Radiator And Cooling System For Leaks

To test the radiator and cooling system for leaks, use the procedure that follows:

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DO NOT loosen the filler or pressure cap on a hot engine. Steam or hot coolant can cause severe burns.

1. Remove the pressure cap from the radiator.

2. Make sure the coolant is over the top of the radiator core.

3. Put the 9S8140 Cooling System Pressurizing Pump Group on the radiator.

4. Get the pressure reading on the gauge to 20 kPa (3 psi) more than the pressure on the pressure cap.

5. Check the radiator for outside leakage.

6. Check all connections and hoses for the cooling system for outside leakage.

7. If you do not see any outside leakage and the pressure reading on the gauge is still the same after five minutes, the radiator and cooling system does not have leakage. If the reading on the gauge goes down and you do not see any leakage, there is leakage on the inside of the cooling system. Make repairs as necessary.

Water Temperature Gauge Test

Check the accuracy of the water temperature gauge if either of the conditions that follow are found:

* The gauge reads normal, but the engine is too hot and a loss of coolant is found.

* The gauge shows that the engine is hot, but no loss of coolant can be found.

Test Location
(1) Plug. (2). Water temperature regulator housing.

Remove plug (1) and install the adapter, seal, and the 4C6500 Thermistor Thermometer Group or the 2F7112 Thermometer. A temperature gauge of known accuracy can also be used to make this check.

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Work carefully around an engine that is running. Engine parts that are hot, or parts that are moving, can cause personal injury.

Start the engine and run it until the temperature reaches the desired range according to the test thermometer. If necessary, put a cover over part of the radiator or cause a restriction of the coolant flow. The reading on the gauge for water temperature should agree with test thermometer within the tolerance range of the gauge.

Water Temperature Regulator Test

1. Remove the regulator from the engine.

2. Heat water in a pan until the temperature is 94°C (202°F). Move the water around in the pan to make it all the same temperature.

3. Hang the regulator in the pan of water. The regulator must be below the surface of the water and it must be away from the sides and bottom of the pan.

4. Keep the water at the correct temperature for ten minutes.

5. After ten minutes, remove the regulator and immediately measure the distance the regulator has opened. Refer to the Specifications for the minimum opening length.

6. If the distance is less than the minimum opening length from the specifications section in this service manual then replace the regulator.

Water Pump Pressure Check

Water Pump Group
(1) Port (alternate heater supply). (2) Port (for engine diagnosis). (3) Ports (heater return).

The pressure rise (increase in pressure or pressure differential) tells if the water pump is operating correctly. Measure the pressure rise across or between port (1) or port (3) and one of two ports (2). Ports (1) and (3) represent water pump outlet pressure. Ports (2) represent water pump inlet pressure (suction). With the engine at operating temperature, under full load condition, the pressure rise must be a minimum of 80 kPa (12 psi).

Belt Tension Chart

Basic Block

Connecting Rod Bearings

The connection rod bearings fit tightly in the bore in the rod. If bearing joints or backs are worn (fretted), check bore size. This can be an indication of wear because of a loose fit.

Connecting rod bearings are available with 0.25 mm (.010 in) and 0.50 mm (.020 in) smaller inside diameter than the original size bearings. These bearings are for crankshafts that have been ground (made smaller than original size).

Main Bearings

Main bearings are available with a larger outside diameter than the original size bearings. These bearings are for cylinder blocks that have had the bore for the main bearings "bored" (made larger than the original size). The size available is 0.50 mm (.020 in) larger outside diameter than the original size bearings.

Main bearings are available with a smaller inside diameter than the original size bearings. These bearings are for cylinder blocks that have a crankshaft that has been ground (made smaller than original size). Main bearings are available with 0.25 mm (.010 in) and 0.50 mm (.020 in) smaller inside diameter than the original size bearings.

Cylinder Block

The bore in the block for main bearings can be checked with the main bearing caps installed without bearings. Tighten the nuts that hold the caps to the torque shown in the Specifications section. Alignment error in the bores must not be more than 0.08 mm (.003 in).

The 1P3537 Dial Bore Gauge Group can be used to check the size of the bore. Special Instruction, GMG00981 is with the group.

1P3537 Dial Bore Gauge Group

Flywheel And Flywheel Housing

Face Run Out (Axial Eccentricity) Of The Flywheel Housing

8T5096 Dial Indicator Group Installed (Typical Example)

If any method other than given here is used, always remember bearing clearance must be removed to get correct measurements.

1. Fasten a dial indicator to the flywheel so the anvil of the indicator will touch the face of the flywheel housing.

2. Put a force on the crankshaft toward the rear before the indicator is read at each point.

Checking Face Runout Of The Flywheel Housing

3. With dial indicator set at "0" (zero) at location (A), turn the flywheel and read the indicator at locations (B), (C) and (D).

4. The difference between lower and higher measurements taken at all four points must not be more than 0.38 mm (.015 in), which is the maximum permissible face run out (axial eccentricity) of the flywheel housing.

Bore Runout (Radial Eccentricity) Of The Flywheel Housing

1. Fasten the dial indicator as shown so the anvil of the indicator will touch the bore of the flywheel housing.

2. With the dial indicator in position at (C), adjust the dial indicator to "0" (zero). Push the crankshaft up against the top of the bearing. Write the measurement for bearing clearance on line 1 in column (C) in the Chart For Dial Indicator Measurements.

8T5096 Dial Indicator Group Installed (Typical Example)

NOTE: Write the dial indicator measurements with their positive (+) and negative (-) notation (signs). This notation is necessary for making the calculations in the chart correctly.

3. Divide the measurement from Step 2 by 2. Write this number on line 1 in columns (B) & (D).

4. Turn the flywheel to put the dial indicator at (A). Adjust the dial indicator to "0" (zero).

5. Turn the flywheel counterclockwise to put the dial indicator at (B). Write the measurements in the chart.

Checking Bore Runout Of The Flywheel Housing

6. Turn the flywheel counterclockwise to put the dial indicator at (C). Write the measurement in the chart.

7. Turn the flywheel counterclockwise to put the dial indicator at (D). Write the measurement in the chart.

8. Add lines I & II by columns.

9. Subtract the smaller number from the larger number in line III in columns (B) & (D). The result is the horizontal eccentricity (out of round). Line III, column (C) is the vertical eccentricity.

10. On the graph for total eccentricity, find the point of intersection of the lines for vertical eccentricity and horizontal eccentricity.

11. If the point of intersection is in the range marked "Acceptable", the bore is in alignment. If the point of intersection is in the range marked "Not Acceptable", the flywheel housing must be changed.

Graph For Total Eccentricity
(1) Total Vertical Eccentricity [mm (in)]. (2) Total Horizontal Eccentricity [mm (in)]. (3) Acceptable. (4) Not Acceptable.

Face Runout (Axial Eccentricity) Of The Flywheel

1. Install the dial indicator as shown. Always put a force on the crankshaft in the same direction before the indicator is read so the crankshaft end clearance (movement) is always removed.

Checking Face Runout Of The Flywheel (Typical Example)

2. Set the dial indicator to read "0" (zero).

3. Turn the flywheel and read the indicator every 90 degrees.

4. The difference between the lower and higher measurements taken at all four points must not be more than 0.15 mm (.006 in), which is the maximum permissible face runout (axial eccentricity) of the flywheel.

Bore Runout (Radial Eccentricity) Of The Flywheel

Checking Bore Runout Of The Flywheel (Typical Example)
(1) 7H1945 Holding Rod (2) 7H1645 Holding Rod (3) 7H1942 Indicator (4) 7H1940 Universal Attachment

1. Install the dial indicator (3) and make an adjustment of the universal attachment (4) so it makes contact as shown.

2. Set the dial indicator to read "0" (zero).

3. Turn the flywheel and read the indicator every 90 degrees.

4. The difference between the lower and higher measurements taken at all four points must not be more than 0.15 mm (.006 in), which is the maximum permissible bore runout (radial eccentricity) of the flywheel.

5. Runout (eccentricity) of the bore for the pilot bearing for the flywheel clutch, must not exceed 0.13 mm (.005 in).

Checking Flywheel Clutch Pilot Bearing Bore

Vibration Damper

Viscous Damper

If the damper is leaking, bent or damaged, or if the bolt holes in the damper are loose fitting, replace the damper. Replacement of the damper is also needed at the time of a crankshaft failure due to torsional forces.

Viscous Vibration Damper
(1) Crankshaft. (2) Weight. (3) Case.

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NOTICE

Inspect the viscous damper for signs of leakage or a dented (damaged) case (3). Either condition can cause weight (2) to make contact with case (3) and affect damper operation.

Electrical System

Test Tools For Electrical System

Most of the tests of the electrical system can be done on the engine. The wiring insulation must be in good condition, the wire and cable connections must be clean and tight, and the battery must be fully charged. If the on-engine test shows a defect in a component, remove the component for more testing.

The service manual Testing And Adjusting Electrical Components, REG00636 has complete specifications and procedures for the components of the starting circuit and the charging circuit.

4C4911 Battery Load Tester

The 4C4911 Battery Load Tester is a portable unit in a metal case for use under field conditions and high temperatures. It can be used to load test all 6, 8 and 12V batteries. This tester has two heavy-duty load cables that can easily be fastened to the battery terminals, and a load adjustment knob on the top permits the current being drawn from the battery to be adjusted to a maximum of 1000 amperes. The tester is cooled by an internal fan that is automatically activated when a load is applied.

The tester has a built in Liquid Crystal Display (LCD) digital voltmeter and amperage meter. The digital voltmeter accurately measures the battery voltage at the battery, through tracer wires buried inside the load cables. The digital amperage meter accurately displays the current being drawn from the battery under test.

NOTE: Make reference to Operating Manual, SEHS9249 for more complete information for use of the 4C4911 Battery Load Tester.

8T0900 AC/DC Clamp-On Ammeter

The 8T0900 AC/DC Clamp-On Ammeter is a completely portable, self-contained instrument that allows electrical current measurements to be made without breaking the circuit or disturbing the insulation on conductors. A digital display is located on the ammeter for reading current directly in a range from 1 to 1200 amperes. If an optional 6V6014 Cable is connected between this ammeter and one of the digital multimeters, current readings of less than 1 ammeter can then be read directly from the display of the multimeter.

A lever is used to open the jaws over the conductor [up to a diameter of 19 mm (.75 in)], and the spring loaded jaws are then closed around the conductor for current measurement. A trigger switch that can be locked in the ON or OFF position is used to turn on the ammeter. When the turn-on trigger is released, the last current reading is held on the display for five seconds. This allows accurate measurements to be taken in limited access areas where the digital display is not visible to the operator. A zero control is provided for DC operation, and power for the ammeter is supplied by batteries located inside the handle.

NOTE: Make reference to Special Instruction, SEHS8420 for more complete information for use of the 8T0900 Clamp-On Ammeter.

6V7070 Heavy-Duty Digital Multimeter

The 6V7070 Heavy-Duty Digital Multimeter is a completely portable, hand held instrument with a digital display. This multimeter is built with extra protection against damage in field applications, and is equipped with seven functions and 29 ranges. The 6V7070 Multimeter has an instant ohms indicator that permits continuity checking for fast circuit inspection. It also can be used for troubleshooting small value capacitors.

The 6V7800 Regular-duty Digital Multimeter (a low cost option to the Heavy-Duty Multimeter) is also available; however, the 6V7800 Multimeter does not have the 10A range or the instant ohms feature of the 6V7070 Multimeter.

NOTE: Make reference to Special Instruction, SEHS7734 for more complete information for use of the 6V7070 and 6V7800 Multimeters.

Battery

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Never disconnect any charging unit circuit or battery circuit cable from battery when the charging unit is operated. A spark can cause an explosion from the flammable vapor mixture of hydrogen and oxygen that is released from the electrolyte through the battery outlets. Injury to personnel can be the result.

The battery circuit is an electrical load on the charging unit. The load is variable because of the condition of the charge in the battery. Damage to the charging unit will result if the connections (either positive or negative) between the battery and charging unit are broken while the charging unit is in operation. This is because the battery load is lost and there is an increase in charging voltage. High voltage will damage, not only the charging unit, but also the regulator and other electrical components.

Use the 4C4911 Battery Load Tester, the 8T0900 Clamp-On Ammeter and the 6V7070 Multimeter to load test a battery that does not hold a charge when in use. See Special Instruction, SEHS7633 for the correct procedure and specifications to use.

Charging System

The condition of charge in the battery at each regular inspection will show if the charging system operates correctly. An adjustment is necessary when the battery is constantly in a low condition of charge or a large amount of water is needed (more than one ounce of water per cell per week or per every 100 service hours).

When it is possible, make a test of the charging unit and voltage regulator on the engine, and use wiring and components that are a permanent part of the system. Off-engine (bench) testing will give a test of the charging unit and voltage regulator operation. This testing will give an indication of needed repair. After repairs are made, again make a test to give proof that the units are repaired to their original condition of operation.

Before the start of on-engine testing, the charging system and battery must be checked as shown in the Steps that follow:

1. Battery must be at least 75 percent (1.225 Sp.Gr.) fully charged and held tightly in place. The battery holder must not put too much stress on the battery.

2. Cables between the battery, starter and engine ground must be the correct size. Wires and cables must be free of corrosion and have cable support clamps to prevent stress on battery connections (terminals).

3. Leads, junctions, switches and panel instruments that have direct relation to the charging circuit must give correct circuit control.

4. Inspect the drive components for the charging unit to be sure they are free of grease and oil and have the ability to operate the charging unit.

Alternator

Make reference to the Specifications section of the complete service manual to find all testing specifications for the alternators and regulators.

No adjustment can be made to change the rate of charge on 24V alternator regulators. If rate of charge is not correct, a replacement of the alternator regulator is necessary.

Starting System

Use a DC Voltmeter to find starting system components which do not function.

Move the start control switch to activate the starter solenoid. Starter solenoid operation can be heard as the pinion of the starter motor is engaged with the ring gear on the engine flywheel.

If the solenoid for the starter motor will not operate, it is possible that the current from the battery did not get to the solenoid. Fasten one lead of the voltmeter to the connection (terminal) for the battery cable on the solenoid. Put the other lead to a good ground. No voltmeter reading shows there is broken circuit from the battery. More testing is necessary when there is a reading on the voltmeter.

The solenoid operation also closes the electric circuit to the motor. Connect one lead of the voltmeter to the solenoid connection (terminal) that is fastened to the motor. Put the other lead to a good ground. Activate the starter solenoid and look at the voltmeter. A reading of battery voltage shows the problem is in the motor. The motor must be removed for further testing. No reading on the voltmeter shows that the solenoid contacts do not close. This is an indication of the need for repair to the solenoid or an adjustment to be made to the starter pinion clearance.

Make a test with one voltmeter lead fastened to the connection (terminal) for the small wire at the solenoid, and the other lead to the ground. Look at the voltmeter and activate the starter solenoid. A voltmeter reading shows that the problem is in the solenoid. No voltmeter reading shows that the problem is in the start switch or the wires for the start switch.

Fasten one voltmeter lead to the start switch at the connection (terminal) for the wire from the battery. Fasten the other lead to a good ground. No voltmeter reading indicates a broken circuit from the battery. Make a check of the circuit breaker and wiring. If there is a voltmeter reading, the problem is in the start switch or in the wires for the start switch.

A starter motor that operates too slow can have an overload because of too much friction in the engine being started. Slow operation of the starter motor can also be caused by short circuit, loose connections and/or dirt in the motor.

To test for correct output of starter motors and starter solenoid, make reference to the Specifications section of the complete service manual.

Starting Motor Adjustment

Solenoid Position Adjustment

The solenoid position on the starting motor controls pinion clearance. If the solenoid position is correct, the pinion clearance is correct. Do the following procedure to adjust the solenoid position.

Solenoid Assembly
(1) Intermediate housing. (2) Solenoid mounting bracket. (3) Bolts. (X) 62.50 + 0.20 - 0.50 mm (2.46 + .008 - .020 in).