SERVICE MANUAL - 3116 DIESEL TRUCK ENGINE 7SF1-UP Caterpillar

Troubleshooting Problem List

Usage:

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

2. Engine Hard To Or Will Not Start Engine Crankshaft Turns Too Slowly

3. Engine Hard To Or Will Not Start Engine Crankshaft Turns Freely

4. Engine Misfiring Or Running Rough

5. Engine Stall At Low RPM

6. Low Power

7. Engine Speed Is Not Stable

8. Engine Overspeeds On Start

9. Too Much Vibration

10. Loud Combustion Noise

11. Valve Train Noise

12. Oil In Cooling System

13. Mechanical Noise (Knock) In Engine

14. Fuel Consumption Too High

15. Too Much Valve Clearance

16. Little Or No Valve Clearance

17. Oil At The Exhaust

18. Engine Has Excessive Early Wear

19. Coolant In Lubrication Oil

20. Too Much Exhaust Smoke (Black Or Gray)

21. Too Much Exhaust Smoke (White Or Blue)

22. Engine Has Low Oil Pressure

23. Engine Uses Too Much Lubrication Oil

24. Above Normal Coolant Temperature

25. Below Normal Coolant Temperature

26. Exhaust Temperature Too High

27. Starter Motor Does Not Turn

28. Alternator Gives No Charge

29. Alternator Charge Rate Is Low Or Not Regular

30. Alternator Charge Too High

31. Alternator Has Noise

32. Fuel In Lubrication Oil

33. Fuel In Coolant

34. Loss Of Coolant

35. Air Inlet Heater

36. Soot In Inlet Manifold

37. Air In Fuel

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

Engine Crankshaft Will Not Turn When Ignition Switch Is On

Probable Cause(s):

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 as shown in the Electrical System of the Testing And Adjusting Section of this Service Manual.

2. Defective switch, defective wiring or connection in switch circuit:

With ignition switch in the "START" position, check voltage at switch connection on starter 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 defective cable or connection between the battery and the starter.

3. Defective cable or connection (battery to starter)

With ignition switch in the "START" position, check voltage at connection of battery cable to starter. 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 defective cable or connection between the battery and the starter.

4. Defective starter solenoid:

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

5. Defective starter motor:

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

6. Transmission or power take-off (if equipped) problem prevents crankshaft from turning:

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

7. Inside problem prevents crankshaft from turning:

If the crankshaft cannot be turned after disconnecting the transmission and/or the power take-off, remove the fuel nozzles 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.

Problem 2: Engine Hard To Or Will Not Start.

Engine Hard To Or Will Not Start

Engine Crankshaft Turns Too Slowly.

Probable Cause(s):

1. Low battery voltage:

2. Defective cable or connection (battery to starter)

3. Oil too thick for free crankshaft rotation:

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

4. Defective starter motor:

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

5. Extra outside loads:

Damage to the power take-off equipment (if equipped) and/or transmission can put extra load on the engine. This prevents free rotation of the crankshaft. To check, disconnect the transmission and power take-off, and start the engine.

6. Mechanical problem inside engine:

Take the engine apart and check all components for damage.

Problem 3: Engine Hard To Or Will Not Start. Engine Crankshaft Turns Freely

Engine Hard To Or Will Not Start

Exhaust Smoke Can Be Seen While Starting

Probable Cause(s):

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 100 rpm. Check the condition of the starting system.

3. Air in the fuel system:

With air in the fuel system the engine will normally be difficult to start, run rough and release a large amount of white smoke. To remove the air from the fuel system, loosen the return line to the fuel tank and put 35 kPa (5 psi) of air pressure to the fuel tank.

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NOTICE

Do not use more than 55 kPa (8 psi) of air pressure in the fuel tank or damage to the tank may result.

Check for leaks at the connections between the fuel tank and the transfer pump. If leaks are found, tighten the connections or replace the lines. If there are no visual leaks, remove the fuel supply line from the tank and connect to an outside fuel supply. If this corrects the problem, the suction (standpipe) inside of the fuel tank has a leak.

4. Low quality fuel:

Remove a small amount of fuel from the tank and check for water in the fuel. If there is water in the fuel, remove fuel from the tank until the tank is free of water. Change the fuel filter and fill the fuel tank with a good quality fuel. The fuel priming pump (if equipped) may be used to fill the fuel filter and fuel gallery (in the cylinder head), from the fuel tank before the engine is started. If there is no water in the fuel, start the engine by using an outside source of fuel. If engine starts correctly using different fuel, remove all fuel from the tank and fill with a good quality fuel.

5. Low fuel pressure:

At starting rpm, the minimum fuel pressure for the fuel transfer pump must be 20 kPa (3 psi) with clean fuel filters. If the fuel pressure is less than 20 kPa (3 psi), look for air in the fuel system. (If fuel in the fuel tank cannot be checked for air, install a sight tube in the fuel return line). If the fuel pressure is still low, check the pressure regulating orifice and the fuel transfer pump for correct operation.

6. Fuel injection timing not correct:

Check and make necessary adjustments as per Testing and Adjusting Section of this Service Manual.

7. Valve adjustment not correct:

Check and make necessary adjustments as per Testing and Adjusting Section of this Service Manual. Intake valve clearance is 0.38 mm (.015 in.) and exhaust valve clearance is 0.64 mm (.025 in.).

8. Defective fuel injector(s):

Remove the fuel injectors and test as per Testing and Adjusting Section of this Service Manual.

9. Low compression:

Refer to Problem No. 4, Engine Misfiring Or Running Rough.

Exhaust Smoke Cannot Be Seen While Starting

Probable Cause(s):

10. No fuel in tank(s):

Check fuel level visually (do not use the fuel gauge only). Be sure tank selection valve is open to the tank with fuel in it. Be sure valve in fuel line between the tanks is open.

11. No fuel from fuel transfer pump:

Loosen the fuel line from the fuel filter to the rear of the cylinder head. With ignition switch in the RUN position and accelerator in the "FUEL ON" position, turn the engine with the starter to be sure there is no fuel from the fuel transfer pump. To find the cause for no fuel, follow Steps (a) through (d) until the problem is corrected.

a. The fuel priming pump (if equipped) may be used to fill the fuel filter and fuel gallery (in the cylinder head), from the fuel tank before the engine is started.

b. Check shutoff solenoid by turning ignition switch to the RUN position. You must hear a sound when the plunger opens. If no sound is heard, make sure there is battery voltage at the solenoid. If the solenoid does not work, install a new solenoid.

c. If you are not using a good quality of fuel at temperatures below -12° C (10° F), it is possible that the fuel in the system can "wax" (not have correct flow characteristics) and cause a restriction in the fuel system. Install a new fuel filter. It may be necessary to drain the complete fuel system and replace with a No. 1 grade of fuel.

d. Check for fuel supply line restriction by removing the fuel supply line for the fuel filter base. Put 35 kPa (5 psi) of air pressure to the fuel tank.

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NOTICE

Do not use more than 55 kPa (8 psi) of air pressure in the fuel tank or damage to the tank may result.

If there is no fuel, or only a weak flow of fuel from the fuel supply line, there is a restriction in the fuel supply line and/or the fuel tank.

12. No fuel to injectors:

a. Check fuel level in the fuel tank and fill if necessary.

b. Install new fuel filters if necessary. Blocked or broken fuel lines should be cleaned or replaced.

c. Defective fuel shutoff solenoid. Remove the fuel shutoff solenoid from the governor. Energize the start connection. If the plunger in the solenoid does not move or fails to stay in the retracted position, replace the solenoid.

d. Check the fuel transfer pump for damage or wear and make replacements as needed.

3. Governor output shaft is not connected to the fuel injector rack control (such as improper assembly during overhaul). Make sure the linkage is correctly engaged.

f. Fuel injector rack control linkage is stuck in the fuel shutoff position. Disconnect the governor output shaft from the fuel injector control linkage. Make sure the injectors are compressed slightly if the rocker arms are removed, then check for binding. Replace linkage as necessary.

g. Malfunction within the governor. Preform a bench test on the governor. Repair or replace the governor if necessary. Bench test the repaired or replacement governor.

13. 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.

Problem 4: Engine Misfiring Or Running Rough

Engine Misfiring And Running Rough

Probable Cause(s):

1. Air in fuel system:

With air in the fuel system the engine will normally be difficult to start, run rough and release a large amount of white smoke. Find the air leak in the fuel system and correct it. If air is in the system, it will generally get in on the suction side of the fuel transfer pump. Refer to Problem No. 37, Air in Fuel.

2. Leak or break in fuel line between transfer pump and cylinder head:

Install a new fuel line.

3. Low fuel pressure:

Make sure there is fuel in the fuel tank. Look for leaks or bad bends in the fuel line between fuel tank and fuel transfer pump. Look for air in the fuel system. (If fuel in the fuel tank cannot be checked for air, install a sight tube in the fuel line). Make sure the fuel filters are clean, then check fuel pressure. The outlet pressure of the fuel transfer pump must be a minimum of 200 kPa (29 psi) at full load speed. If fuel pressure is lower than the above pressure, check the fuel transfer pump and fuel pressure regulating orifice at the fuel return line.

4. Fuel has a high "Cloud Point":

The fuel "Cloud Point" is the temperature at which wax begins to form in the fuel. If the atmospheric temperature is lower than the "Cloud Point" of the fuel, wax will form and plug the fuel filter. Change the filter and drain the fuel tank and the complete fuel system. Replace the fuel with a better grade of fuel with a lower "Cloud Point".

4. Defect in fuel injector(s):

a. Temperature of an exhaust manifold port, when the engine runs at low idle speed, can be an indication of the condition of a fuel injector. Low temperature at an exhaust manifold port is an indication of no fuel to the cylinder. This can possible be an indication of an injector with a defect. Extra high temperature at an exhaust manifold port can be an indication of too much fuel to the cylinder, also caused by an injector with a defect. NOTE: Only experienced mechanics should use this technique. There can be wide operating temperature variations on the exhaust manifold and the injectors can still be operating correctly.

b. Check the height of all injectors to make sure there are no seized injectors.

c. Check for free travel of all injector rack bars.

d. If an injector is suspected to be defective, check the injector. Use the 1U6661 Pop (Injector) Tester to check the injector for proper operation. Refer to Special Instruction, Form No. SEHS8867 for additional information.

6. Valve adjustment not correct:

Check and make necessary adjustments as per Testing and Adjusting Section of this Service Manual. Intake valve clearance is 0.38 mm (.015 in) and exhaust valve clearance is 0.64 mm (.025 in). Also check for a bent or broken push rod.

7. Fuel injection timing not correct:

Check and make necessary adjustments as per Testing and Adjusting Section of this Service Manual.

8. Bent or broken push rod:

Check injectors height for any seized injectors and/or bent or broken pushrods. Replace pushrods as necessary.

9. Fuel injector control linkage binding:

Disconnect the governor output shaft from the fuel injector control linkage. Check the linkage for smooth operation. If linkage still appears to be binding, remove injectors. With injector springs compressed, check injector racks for smooth operation. Replace injectors with "sticky" racks. Check linkage again for smooth operation. If still binding, loosen bolts holding linkage to cylinder head. Operate the linkage by hand. If binding is still present after retightening the bolts, replace the control linkage.

10. 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. Tighten the bolts that hold the cylinder head according to the Specifications Section of this Service Manual.

11. 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, Form No. SEHS8712.

12. Improper injector synchronization:

Check and make necessary adjustments as per Testing and Adjusting Section of this Service Manual.

Problem 5: Engine Stall At Low RPM

Engine Stall At Low RPM

Probable Cause(s):

1. Fuel pressure is low:

Make sure there is fuel in the fuel tank. Look for leaks or bad bends in the fuel line between fuel tank and fuel transfer pump. Look for air in the fuel system. Make sure the fuel filters are clean, then check fuel pressure. The outlet pressure of the fuel transfer pump must be a minimum of 200 kPa (29 psi) at full load speed. If fuel pressure is lower than the above pressure, check the fuel transfer pump and fuel pressure regulating orifice at the fuel return line.

2. Low idle rpm too low:

Make adjustment to governor so low idle rpm is the same as given in the Fuel Setting And Related Information Fiche.

3. Engine accessories:

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

4. Defect in fuel injector(s):

Refer to Problem No. 4, Engine Misfiring Or Running Rough.

5. Fuel injector control linkage binding:

6. Problem with the governor:

Bench test the governor. If the governor cannot be properly adjusted during bench testing, repair or replace the governor. Bench test the repaired or replacement governor.

Problem 6: Low Power

Low Power

Probable Cause(s):

1. Dirty fuel filters:

Install new fuel filters.

2. Oil level too high:

Remove dipstick and check oil level. If level is too high, drain out 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 rising due to a fuel leak or other engine problem.

3. 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. Defect in the air to air aftercooler. Check temperature of inlet and outlet air from air cooler. Remove any external or internal restrictions.

4. Fuel pressure is low:

5. Low quality fuel or water in fuel:

Remove the fuel from the fuel tank. Install new fuel filter. Put a good grade of clean fuel in the fuel tank.

6. Defect in fuel injector(s):

Refer to Problem No. 4, Engine Misfiring Or Running Rough.

7. Wrong valve clearance:

Check and make necessary adjustments as per Testing and Adjusting Section of this Service Manual.

8. Wrong fuel injection timing dimension:

Check and make necessary adjustments as per Testing and Adjusting Section of this Service Manual.

9. Fuel setting incorrect:

Check and make necessary adjustments as per Testing and Adjusting Section of this Service Manual. See Fuel Setting And Related Information Fiche for the correct fuel setting.

10. Fuel injector control linkage binding:

11. Problem with the governor:

Bench test the governor. If the governor cannot be properly adjusted during bench testing, repair or replace the governor. Bench test the repaired or replacement governor.

12. Turbocharger has carbon deposits or other cause of friction:

Make inspection and repair turbocharger as necessary.

Problem 7: Engine Speed Is Not Stable

Engine Speed Is Not Stable

Probable Cause(s):

1. Fuel pressure is low:

2. Engine misfiring:

Refer to Problem No. 4, Engine Misfiring Or Running Rough.

3. Fuel injector control linkage is binding:

Disconnect the governor output shaft from the fuel injector rack control linkage. Check the linkage for smooth movement. If linkage still appears to be binding, remove injectors. With injector springs compressed, check injector racks for smooth operation. Replace injectors with "sticky" racks. Check linkage again for smooth operation. If still binding, loosen bolts holding linkage to cylinder head. Operate the linkage by hand. If binding is still present after retightening the bolts, replace the control linkage.

4. Improper injector synchronization:

Check and make necessary adjustments as per Testing and Adjusting Section of this Service Manual.

5. Problem with the governor:

Bench test the governor. If the governor cannot be properly adjusted during bench testing, repair or replace the governor. Bench test the repaired or replacement governor.

Problem 8: Engine Overspeeds On Start

Engine OverSpeeds On Start

Probable Cause(s):

1. Fuel control linkage:

Improper assembly after overhaul, linkage not free, stuck in fuel-on position, governor output shaft not connected to fuel injector control linkage. Make repairs or replacements as needed.

2. Governor problem:

Bench test the governor. If the governor cannot be properly adjusted during bench testing, repair or replace the governor. Bench test the repaired or replacement governor.

Problem 9: Too Much Vibration

Too Much Vibration

Probable Cause(s):

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. Vibration damper has a defect:

Install a new vibration damper.

3. Engine supports are loose, wrong or have a defect:

Tighten all mounting bolts. Install new components if necessary.

4. Driven equipment is not in alignment or is out of balance:

Check alignment and balance, correct if needed.

5. Misfiring or running rough:

Refer to Problem No. 4, Engine Misfiring Or Running Rough.

6. Improper injector synchronization:

Check and make necessary adjustments as per Testing and Adjusting Section of this Service Manual.

Problem 10: Loud Combustion Noise (Sound)

Loud Combustion Noise (Sound)

Probable Cause(s):

1. Air in fuel system:

With air in the fuel system the engine will normally be difficult to start, run rough and release a large amount of white smoke. If air is in the system, it will generally get in on the suction side of the fuel transfer pump. Check for leakage at the connections between the fuel tank and the fuel transfer pump. Check for leakage at the connections between the fuel tank and the fuel transfer pump. If leaks are found, tighten the connections or replace the lines. If there are no visual leaks, remove the fuel supply line from the tank and connect it to an outside fuel supply. If this corrects the problem, the suction line (standpipe) inside the fuel tank has a leak. If this does not correct the problem, install a sight tube in the fuel return line and check the injectors to verify that they are properly seated. This can be accomplished by moving each injector (one at a time) to the "FUEL ON" position momentarily and checking the sight tube for any increase in air bubbles. Push on the rack bar on the exhaust manifold side of the injector to move the injector to the "FUEL ON" position. If an increase in air is found, then remove that injector. Check the tip seal (O-ring) and replace it if it is found to be defective. Inspect the injector sleeve for a smooth sealing surface for the injector to seat on. If any defects are noted, the sleeve can be reamed or it can be replaced if necessary.

The temperature of an exhaust manifold port can be an indication of a cylinder that has air being delivered to it. Check the exhaust manifold temperatures and compare the results. A lower than normal cylinder temperature indicates that the cylinder may be receiving air from the injector. The color of the exhaust smoke can also indicate which cylinder has a combustion leak. Move each injector (one at a time) to the "FUEL ON" position momentarily while checking the color of the exhaust smoke. The cylinder that has air will produce smoke that is gray or white in color.

2. Low quality fuel:

Remove the fuel from the fuel tank. Install new fuel filter. Put a good grade of clean fuel in the fuel tank.

3. Wrong fuel injection timing dimension:

Check and make necessary adjustments as per Testing and Adjusting Section of this Service Manual.

4. Improper injector synchronization:

Improper injector synchronization will cause more fuel to be delivered to one cylinder. This will cause a combustion "knock". The over fueling cylinder(s) can be determined by moving each injector (one at a time) to the "FUEL ON" position and listening for a combustion "knock". Check and make necessary adjustments as per Testing and Adjusting Section of this Service Manual.

5. Defect in fuel injector(s):

Use the 1U6661 Pop (Injector) Tester to check the injectors for proper operation. Refer to Special Instruction, Form No. SEHS8867 for additional information.

6. Mechanical problem:

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

Problem 11: Valve Train Noise

Valve Train Noise

Probable Cause(s):

1. Too much valve clearance:

Check and make necessary adjustments as per Testing and Adjusting Section of this Service Manual.

2. Damage to valve springs, locks, 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.

Problem 12: Oil In Cooling System

Oil In Cooling System

Probable Cause(s):

1. Defect in core of engine oil cooler:

Inspect cooler and make a replacement or repair defective 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. Tighten the bolts that hold the cylinder head according to the Specifications Section of this Service Manual.

Problem 13: Mechanical Noise (Knock) In Engine

Mechanical Noise (Knock) In Engine

Probable Cause(s):

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. Defect in accessory equipment:

Repair as needed or install new components.

Problem 14: Fuel Consumption Too High

Fuel Consumption Too High

Probable Cause(s):

1. Fuel system leaks:

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

b. Check for a defective O-ring seal on the top of the injector. Remove the fuel supply line at the rear of the cylinder head and pressurize the cylinder head (the return to fuel tank line will have to be blocked). Look for fuel leaking from the injectors where they seal with the cylinder head. If fuel is leaking from an injector, remove the injector and replace the upper O-ring seal. Also depending on the amount of leakage an oil sample should be taken and checked for fuel dilution. Change oil and oil filter if necessary. While the cylinder head is pressurized, check for porosity around the oil drain back holes. If porosity is found, replace the cylinder head. If fuel is found in the coolant, then check the injector sleeves in the cylinder head for cracks or erosion. If defects are found, then remove the sleeves and install new sleeves.

2. Fuel setting too high:

Check and make necessary adjustments as per Testing and Adjusting Section of this Service Manual.

3. Fuel and combustion noise (knock):

See Problem no. 4, Misfiring and Running Rough. See Problem No. 10, Loud Combustion Noise.

4. Wrong fuel injection timing dimension:

Check and make necessary adjustments as per Testing and Adjusting Section of this Service Manual.

5. Defect in fuel injectors:

Use the 1U6661 Pop (Injector) Tester to check the injectors for proper operation. Refer to Special Instruction, Form No. SEHS8867 for additional information.

Problem 15: Too Much Valve Clearance

Too Much Valve Clearance

Probable Cause(s):

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 as per Testing and Adjusting Section 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 as per Testing and Adjusting Section 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 as per Testing and Adjusting Section of this Service Manual.

4. Worn lobes on camshaft:

Check valve clearance. Check for free movement of valves or bent valve stems. Install a new camshaft. Install new valve lifters. Check and make necessary adjustments as per Testing and Adjusting Section 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.

Problem 16: Little Or No Valve Clearance

Probable Cause(s):

1. Worn valve seat or face of valve:

Reconditioning of cylinder head is needed. Check and make necessary adjustments as per Testing and Adjusting Section of this Service Manual.

Problem 17: Oil At The Exhaust

Oil At The Exhaust

Probable Cause(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:

See the Specifications Section of this Service Manual 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, Form No. SEHS8712. Inspect and install new parts as needed.

5. Scored or worn cylinder walls:

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

Problem 18: Engine Has Excessive Early Wear

Engine Has Excessive Early Wear

Probable Cause(s):

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. Fuel leakage into lubrication oil:

This will cause high fuel consumption and low engine oil pressure. This condition may also increase the oil level in the crankcase. Make repairs if leaks are found. Install new parts were needed.

4. Improper lubrication oil:

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

5. Improper engine settings:

Check timing, injector synchronization, fuel setting, and valve settings. Refer to the Testing And Adjusting Section of this Service Manual.

Problem 19: Coolant In Lubrication Oil

Coolant In Lubrication Oil

Probable Cause(s):

1. Failure of the oil cooler core:

Install a new core for the defective 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 in injector bore.

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

4. Crack or defect in cylinder head:

Install a new cylinder head.

5. Crack or defect in cylinder block:

Install a new cylinder block.

Problem 20: Too Much Exhaust Smoke (Black Or Gray):

Too Much Exhaust Smoke

Engine Runs Smoothly

Probable Cause(s):

1. Engine used at an altitude above 762 m (2500 ft):

Consult with the Fuel Setting And Related Information Fiche specifications for proper operating altitude for engine certifications.

2. Not enough air for combustion:

A. Restriction in air cleaner:

If the air cleaner has a restriction indicator, see if the red piston is in view. If there is no restriction indicator, restriction can be checked with a water manometer or a vacuum gauge (which measures in inches of water). Make a connection of the piping between the air cleaner and the air inlet of the turbocharger. Check with the engine running at full load rpm. Maximum restriction is 762 mm (30 in) of water. If a gauge is not available, visually check the air cleaner element for dirt. If the element is dirty, clean the element or install a new element.

B. Air inlet piping damage or restriction:

Make a visual inspection of the air inlet system and check for damage to piping, rags in the inlet piping, or damage to the rain cap or the cap is pushed too far onto the inlet pipe. If no damage is seen, check the inlet restriction with a clean air cleaner element.

C. Turbocharger not operating properly:

Check turbocharger for proper operation.

D. Engine used in a lug condition:

"Lugging" (when the vehicle is used in a gear too high for engine rpm to go up as accelerator pedal is pushed farther down, or when the vehicle is used in a gear where engine rpm goes down with accelerator pedal at maximum travel) the engine causes a reduction in the intake of air with full fuel delivery to the cylinders. Because there is not enough air to burn all the fuel, the fuel that is not used comes out of the exhaust as black smoke. To prevent "lugging" the engine, use a gear where the engine can have "acceleration" (increase in speed) under load.

3. Exhaust system restriction:

Make a visual inspection of the air inlet system and check for damage to piping or a defective muffler. If no damage is found, check the system by checking the back pressure from the exhaust (pressure difference measurement between exhaust outlet and atmosphere). The back pressure must not be more than 686 mm (27 in) of water. If a gauge is not available, check by removing the exhaust pipes from the exhaust manifold. With the exhaust pipes removed, start the engine and load the engine on a chassis dynamometer to see if the problem is corrected.

4. Low quality fuel:

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

5. Fuel setting incorrect:

Check and make necessary adjustments as per Testing and Adjusting Section of this Service Manual. See Fuel Setting And Related Information Fiche for the correct fuel setting.

6. Wrong fuel injection timing dimension:

Check and make necessary adjustments as per Testing and Adjusting Section of this Service Manual.

7. Valve adjustment is not correct or valve leakage:

Check and make necessary adjustments as per Testing and Adjusting Section of this Service Manual. Intake valve clearance is 0.38 mm (.015 in) and exhaust valve clearance is 0.64 mm (.025 in).

8. Defective fuel injectors:

Defective fuel injectors will normally cause the engine to "misfire" (injection not regular) and run rough, but can cause too much smoke with the engine running smooth. Remove and check the fuel injectors. Use the 1U6661 Pop (Injector) Tester to check the injectors for proper operation. Refer to Special Instruction, Form No. SEHS8867 for additional information.

9. Governor problem:

Bench test the governor. If the governor cannot be properly adjusted during bench testing, repair or replace the governor. Perform a bench test on repaired or replacement governor. Verify that the settings are correct for air fuel ratio control.

Engine Runs Rough

Probable Cause(s):

10. Misfiring cylinders:

Refer to Problem No. 4, Engine Misfiring Or Running Rough.

11. Fuel injection timing not correct:

Check and make necessary adjustments as per Testing and Adjusting Section of this Service Manual.

12. Air in fuel system:

If this does not correct the problem, install a sight tube in the fuel return line and check the injectors to verify that they are properly seated. This can be accomplished by moving each injector (one at a time) to the "FUEL ON" position momentarily and checking the sight tube for any increase in air bubbles. Push on the rack bar on the exhaust manifold side of the injector to move the injector to the "FUEL ON" position. If an increase in air is found, then remove that injector. Check the tip seal (O-ring) and replace it if it is found to be defective. Inspect the injector sleeve for a smooth sealing surface for the injector to seat on. If any defects are noted, the sleeve can be reamed or it can be replaced if necessary.

Problem 21: Too Much Exhaust Smoke (White Or Blue)

Too Much Exhaust Smoke

White Smoke

Probable Cause(s):

1. Cold outside temperatures:

When the air outside is cold, the cylinder temperature is cooler. Not all the fuel will burn in the cylinders. The fuel which does not burn comes out the exhaust as white smoke. White smoke is normal in cold temperatures until the engine operates long enough to become warm. There will be less white smoke if No. 1 diesel fuel is used.

2. 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. If long idle periods are necessary, use No. 1 diesel fuel.

3. Low quality fuel:

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

4. Air in fuel system:

5. Air inlet heater is not operating properly:

Check the operation of the air inlet heater. Refer to Problem No. 36, Air Inlet Heater.

6. Valve adjustment not correct:

Check and make necessary adjustments as per Testing and Adjusting Section of this Service Manual.

7. Fuel injection timing not correct:

Check and make necessary adjustments as per Testing and Adjusting Section of this Service Manual.

8. Misfiring cylinder(s):

Refer to Problem No. 4, Engine Misfiring Or Running Rough.

9. Defective fuel injector(s):

Blue Smoke

Probable Cause(s):

10. Oil level in engine too high:

Do not put too much oil in the crankcase. If the oil level in the crankcase goes up as the engine is used, check for fuel in the lubrication oil. Refer to Problem No. 33, Fuel In Lubrication Oil.

11. Failure of turbocharger oil seal:

Check inlet manifold for oil and repair turbocharger.

12. Worn valve guides:

See the Specifications Section of this Service Manual for the maximum permissible wear of the valve guides. If necessary, recondition the cylinder head.

13. 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, Form No. 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 Specification Section of this Service Manual. Repair and replace parts as necessary.

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

14. Wear or damage to pistons:

Check piston ring to groove clearance. Pistons which have worn grooves and pistons with damage or defects 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.

Problem 22: Engine Has Low Oil Pressure

Engine Has Low Oil Pressure

Probable Cause(s):

1. Defect in 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. Diesel fuel in lubrication oil:

Find the place where diesel fuel gets into the lubrication oil. Pressure check the fuel system to check for porosity in the cylinder head or a leaking O-ring seal on an injector. Make repairs as needed. Remove the lubrication oil that has diesel fuel in it. Install new oil filter. Fill the engine with clean oil. Refer to Problem No. 32, Fuel In Lubrication Oil.

4. Oil pump has a defect:

Repair or replace oil pump.

5. Oil pump suction pipe has a defect:

Replacement of pipe is needed.

6. 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.

7. Too much clearance between rocker arm shaft and rocker arms:

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

8. Too much clearance between camshaft and camshaft bearings:

Install new camshaft and camshaft bearings if necessary.

9. Too much clearance between crankshaft and crankshaft bearings:

Inspect the bearings and make replacement as necessary.

Problem 23: Engine Uses Too Much Lubrication Oil

Engine Uses Too Much Lubrication Oil

Probable Cause(s):

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:

See the Specifications Section of this Service Manual for the maximum permissible wear of the valve guides. If necessary, recondition the cylinder head.

Problem 24: Above Normal Coolant Temperature

Above Normal Coolant Temperature

Probable Cause(s):

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 wrong 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. Improper mixture:

Check the mixture of antifreeze and water. The mixture should be approximately 50 % water and 50 % antifreeze with a 3 to 6 % 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 defective 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 8T0470 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 cab 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:

* 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.

* 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 recommendations of the Truck Manufacturer.

* Winter fronts can cause high coolant temperatures on warm days if left installed. Winter fronts can also cause low power problems with air to air aftercooling.

* Shutters not opening correctly can cause overheating due to the restriction of air movement across the radiator. Check the opening temperature of the shutters. The shutters must be closed at a temperature below the fully open temperature of the water temperature regulators. Shutters can also cause low power problems with air to air aftercooling.

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. Wrong fan, fan or shroud not in correct position:

A wrong 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. Make sure the fan size, fan shroud and position of the fan and shroud are according to the recommendations of the Truck Manufacture.

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):

Defective 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. Hoses must be changed after 50,000 miles or a year of use. 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 mmeasures 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 635 mm (25 in) 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 defective muffler. If no damage is found, check the exhaust system for back pressure from the exhaust (pressure difference measurement between exhaust outlet and atmosphere). The back pressure must not be more than 1016 mm (40 in) of water. 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, see the Testing and Adjusting Section of this Service Manual.

16. Defective 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. The clearance between the impeller and the housing is 0.28 to 0.84 mm (.011 to .033 in.).

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. 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. To get better cooling, use the truck in a lower gear.

20. Operation at high altitude:

The cooling capacity of the cooling system goes down as the truck is used 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" (when the truck is used in a gear too high for engine rpm to go up as accelerator pedal is pushed farther down, or when the truck is used in a gear where engine rpm goes down with accelerator pedal at maximum travel) the engine causes the engine rpm and fan rpm to be low. 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.

22. Fuel setting:

A high fuel setting causes a high heat rejection. If the engine cooling system is designed for a particular heat rejection and it is changed the cooling system is no longer capable of cooling the engine.

23. Fuel injection timing:

Check and make necessary adjustments as per Testing and Adjusting Section of this Service Manual.

Problem 25: Below Normal Coolant Temperature

Below Normal Coolant Temperature

Probable Cause(s):

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, and a very slow speed or downhill travel can cause below normal heating because of the low heat input of the engine. The installation of shutters helps to correct this condition.

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 truck 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 vehicle has a light load.

Problem 26: Exhaust Temperature Is Too High

Exhaust Temperature Is Too High

Probable Cause(s):

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. Wrong fuel injection timing dimension:

Check and make necessary adjustments as per Testing and Adjusting Section of this Service Manual.

5. Fuel setting too high:

Check and make necessary adjustments as per Testing and Adjusting Section of this Service Manual. See Fuel Setting And Related Information Fiche for the correct fuel setting.

6. Engine used in a lug condition:

Problem 27: Starter Motor Does Not Turn

Starter Motor Does Not Turn

Probable Cause(s):

1. Low or no battery voltage:

2. Defective switch, defective wiring or connection in switch circuit:

3. Defective starter solenoid:

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

4. Defective starter motor:

5. Inside problem prevents crankshaft from turning:

Problem 28: Alternator Gives No Charge

Alternator Gives No Charge

Probable Cause(s):

1. Loose drive belt for alternator:

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

2. Charging or ground return circuit or battery connections have a defect:

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

3. Brushes have a defect:

Install new brushes.

4. Rotor (field coil) has a defect:

Install a new rotor.

Problem 29: Alternator Charge Rate Is Low Or Not Regular

Alternator Charge Rate Is Low Or Not Regular

Probable Cause(s):

1. Loosen drive belt for alternator:

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

2. Charging or ground return circuit or battery connections have a defect:

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

3. Alternator regulator has a defect:

Replace the alternator regulator.

4. Alternator brushes have a defect:

Install new brushes.

5. Rectifier diodes have a defect:

Make replacement of rectifier diode that has a defect.

6. Rotor (field coil) has a defect:

Install a new rotor.

Problem 30: Alternator Charge Too High

Alternator Charge Too High

Probable Cause(s):

1. Alternator or alternator regulator has loose connections:

Tighten all connections to alternator or alternator regulator.

2. Alternator regulator has a defect:

Replace the alternator regulator.

Problem 31: Alternator Has Noise

Alternator Has Noise

Probable Cause(s):

1. Drive belt for alternator is worn or has a defect:

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. Tighten pulley nut according to the Specifications Section of 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.

Problem 32: Fuel In Lubrication Oil

Fuel In Lubrication Oil

Probable Cause(s):

1. Defective seal on fuel injector:

Check for a defective O-ring seal on the top of the injector. Remove the fuel supply line at the rear of the cylinder head and pressurize the cylinder head (the return to fuel tank line will have to be blocked). Look for fuel leaking from the injectors where they seal with the cylinder head. If fuel is leaking from an injector, remove the injector and replace the upper O-ring seal. Also depending on the amount of leakage an oil sample should be taken and checked for fuel dilution. Change oil and oil filter if necessary.

2. Defective fuel injectors:

A defective fuel injector can allow fuel to leak into the lubrication oil. Remove and check the fuel injectors. Use the 1U6661 Pop (Injector) Tester to check the injectors for proper operation. Refer to Special Instruction, Form No. SEHS8867 for additional information.

3. Porosity in the cylinder head:

Pressurize the fuel gallery and check for porosity around the oil drain back holes. If porosity is found, replace the cylinder head.

4. Porosity in fuel filter base

Check the fuel filter base for porosity or defects. Fuel can be transferred to the crankcase through a defective fuel filter base.

Problem 33: Fuel In Coolant

Probable Cause:

1. Defect in cylinder head sleeve:

Remove unit injectors and inspect sleeves in cylinder head injector bores. Look for any signs of cavitation erosion or cracks. If any problems are seen, remove the sleeve and replace with new parts.

Problem 34: Loss Of Coolant

Loss Of Coolant

A. 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 the heater 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. Tighten the bolts that hold the cylinder head according to the Specifications Section of this Service Manual.

B. Coolant Leaks At The Overflow Tube

Probable Cause(s):

6. Defective 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. See Problem No. 24, 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 Truck Manufacturer.

9. Cylinder head gasket leakage, or crack(s) in cylinder head or cylinder block:

C. Internal Leakage

Probable Cause(s):

10. Erosion or crack(s) in injector sleeves:

If fuel is detected in the coolant, a possible cause is a defective injector sleeve. Remove the injectors and inspect the sleeves for cavitation erosion or cracks. Replace any defective sleeves.

11. 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.

12. 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.

13. 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.

Problem 35: Air Inlet Heater

Inlet Air Heater

Probable Cause(s):

1. Heater stays on longer than allotted time-any cycle:

Replace the air inlet heater control module. Note: Cycle times are approximate only. Some variance does not necessarily indicate a system failure.

2. Heater does not come on:

Check for the following:

*a defective control module.*a defective oil pressure switch (regular heat cycle only).*a defective coolant sensor.*a defective heater element.*a defective power relay (magnetic switch).

Show/hide table

To avoid personal injury (burns), make sure the coolant temperature is below 37.8°C (100 °F) before performing any tests.

3. System Check:

NOTE: The procedures that follow are step-by-ste diagnostic checks that must be performed in sequence. Failure to do so may result in incorrect diagnosis and unnecessary expense.

4. Lamp Test:

a. Inspect the lamp, replace if necessary.

b. Check lamp wiring harness for a cut/broken wire or poor connection.

c. If after inspecting the lamp and harness the lamp still does not illuminate proceed with the cycle tests that follow.

NOTE: If the coolant temperature is below 18.3 ± 2.7 °C (65 ± 5 °F), the system should go directly from the lamp test into the pre-heat cycle (light will not turn off).

5. Pre-Heat Cycle:

With the help of a co-worker, turn the ignition switch to the "RUN" position and feel the power relay (magnetic switch) for a "click", indicating the relay is energized. (The cover must be removed from the controller to gain access to the magnetic switch). If no click is felt when the switch is turned to the "RUN" position, proceed as follows:

NOTE: It may be necessary to reset the ignition switch (turn off then back on), periodically while preforming these diagnostic checks. The pre-heat cycle times out in thirty seconds, and any tests performed after that period will lead to an incorrect diagnosis.

a. Disconnect the electrical connector at the control module. Attach a voltmeter between terminal "F" and terminal "A" of the vehicle end of the wiring harness.

b. With the ignition in the "RUN" position, a reading of 12 volts should be evident.

c. If no reading is noted, inspect the vehicle's wiring system for a blown fuse, cut/broken wire or a poor connection. Check both the power (terminal "F") and ground (terminal "A") wires.

d. If a reading of 12 volts is noted, reconnect the connector.

e. Disconnect the wiring harness at the coolant sensor. With a small "jumper" wire, connect the two (2) terminals on the module end of the wiring harness.

f. With the help of a co-worker, turn the ignition switch to the "RUN" position and feel the power relay (magnetic switch) for a "click", indicating the relay is energized.

g. If the click is felt, the temperature is above 29.4 °C (85 °F) the coolant sensor has not reset to the closed position due to the coolant temperature not reaching 18.3 °C (65 °F) or below, or the coolant sensor is defective. Perform the Coolant Sensor Check, and replace the coolant sensor if necessary.

h. If a click is not felt with the coolant sensor leads jumped, attach a test light at the power relay (magnetic switch). Power should be present at both terminals on the coil side of the relay.

1. If power is present on the module side, but not on the heater side of the relay, replace the relay.

2. If power is present on both sides of the relay, remove the ground lead from the relay. (The ground wire attaches to terminal "D" of the control module). Ground the relay to the cylinder block. If the relay energizes, the control module is defective and must be replaced.

i. If the power relay (magnetic switch) energizes, yet the heater does not operate, use a test light to check for power on the contact side of the relay. Lack of potential indicates a wiring problem. Check the vehicle's harness for a cut/broken wire or a poor connection.

j. If power is present on the heater side of the relay, and the heater is still not operating, inspect the heater ground wire. If there are no defects, perform the Heater Element Check.

6. Crank Heat Cycle:

If the heater does not come on when the engine is being cranked, proceed as follows:

A. Follow Steps a-j of the Pre-Heat Cycle Test. If the system operation is correct to this point, allow the heater to remain in pre-heat mode until it times out (30 seconds). Feel the power relay (magnetic switch) for a second click as the heater is deactivated. If the relay does not click a second time, or stays on longer than 30 seconds, replace the control module.

B. After the 30 second period the heater should be deactivated. With the help of a co-worker, turn the ignition switch from the "RUN" position to the "START" position and feel the power relay (magnetic switch) for a click. If none is present proceed as follows:

a. Disconnect the electrical connector at the control module. Attach a voltmeter between terminal "B" and terminal "A" of the vehicle end of the wiring harness.

b. With the ignition in the "START" position a reading of 12 volts should be present.

c. If no reading is noted, inspect the vehicle's wiring system for a blown fuse, cut/broken wire or a poor connection. Check both the power (terminal "B") and ground (terminal "A") wires.

d. If a reading of 12 volts is noted, replace the control module.

NOTE: The heater should continue to operate for a maximum of 60 seconds after the ignition is released from the "START" position if the engine is not operating. If the heater does not operate, or operates for longer than 60 seconds, replace the control module.

7. Regular Heat/Run Cycle:

If the heater does not come on when the engine is started and is running, proceed as follows:

a. Follow Steps a-j of the Pre-Heat Cycle Test with the only exception being that the engine is started and running. If the system does not function with the coolant sensor jumped, proceed as follows:

b. Leave the coolant sensor leads jumped.

c. Disconnect the wiring harness at the oil pressure switch. Using a voltmeter, check for power on the vehicle end of the wiring harness.

d. Inspect the vehicle's wiring harness for a blown fuse, cut/broken wire, or a poor connection if no power is present.

e. If a reading of 12 volts is noted, connect the two oil pressure switch terminals on the vehicle end of the wiring harness with a small "jumper" wire.

f. With the help of a co-worker, start the vehicle and feel for the click in the power relay (magnetic switch).

g. If the relay clicks, replace the oil pressure switch.

NOTE: Before replacing the oil pressure switch make certain the oil pressure at the oil manifold is greater than 241 ± 69 kPa (35 psi ± 10 psi) with the engine running.

h. If the coolant sensor and pressure switch are both jumped and the power relay (magnetic switch) does not click, then the control module is defective.

8. Heater Element Check:

If, during the inspection of the controller, no malfunction can be found and the heater still does not operate, the heater element may be defective. Inspect the heater element as follows:

Using an ohmmeter, measure the resistance across the two terminals of the heater. There should be very little resistance to the current flow.

a. If the meter reads an infinite resistance, the heater element is defective and should be replaced.

b. If the ohmmeter reads a very low resistance, check the ground wire from the heater to the cylinder head.

9. Coolant Sensor Check

The coolant sensor used in the inlet air heater is designed to open at 29.4 ± 2.7 °C (85 ± 5 °F), and reset (close) at 18.3 ± 2.7 °C (65 ± 5 °F). To test the sensor proceed as follows:

a. Remove the sensor from the water temperature regulator housing and place in a container of cold water [10 °C (50 °F) or less].

b. Connect an ohmmeter across the leads of the sensor. After allowing the sensor temperature to equalize with the water temperature, make certain that the temperature is still near 10 °C (50 °F). The sensor should be closed at this point and offer very little resistance.

c. Place a thermometer in the container and heat the water slowly while stirring. At 29.4 ± 2.7 °C (85 plusmn; 5 °F) the reading should change to infinite resistance (open switch).

d. Cool the water by slowly adding ice while stirring. When the water temperature reaches 18.3 ± 2.7 °C (65 ± 5 °F) the reading should change from infinite to minimal resistance.

e. If any of these conditions are not met, the sensor should be replaced.

10. Oil Pressure Switch Check:

The oil pressure switch used in the inlet air heater system is designed to be open below 241 ± 69 kPa (35 psi ± 10 psi) and closed above 241 ± 69 kPa (35 psi ± 10 psi). To test the oil pressure switch proceed as follows:

a. With the engine stopped, disconnect the lead to the oil pressure switch in the oil manifold.

b. Connect an ohmmeter across the oil pressure switch leads on the controller side of the wiring harness.

c. With the engine stopped [0 kPa (0 psi) oil pressure], the ohmmeter should read infinite resistance (open circuit).

d. Start the engine and increase the RPM until the oil pressure is 241 ± 69 kPa (35 psi ± 10 psi). At some point in this range, the resistance should go from infinity to zero (0) ohms (closed circuit).

e. If either of these conditions are not met, the oil pressure switch should be replaced.

Problem 36: Soot In The Inlet Manifold

Probable Cause:

1. On 3116 Engines a small amount of soot is normal. This is due to the design characteristics of the engine. Valve overlap allows the intake to open slightly before the exhaust stroke has been completed, which will allow some soot to be pushed into the inlet manifold.

Problem 37: Air In Fuel

Probable Cause:

NOTE: The fuel priming pump (if equipped) may be used to remove the air from the fuel filter and fuel gallery (in the cylinder head), and fill the fuel system with fuel from the fuel tank before the engine is started.

If there are no visual leaks, remove the fuel supply line from the tank and connect it to an outside fuel supply. If this corrects the problem, the suction line (standpipe) inside the fuel tank has a leak.

The color of the exhaust smoke can also indicate which cylinder has a combustion leak. Move each injector (one at a time) to the "FUEL ON" position momentarily while checking the color of the exhaust smoke. The cylinder that has air will produce smoke that is gray or white in color.