- Gather information about the complaint from the operator.
- Verify that the complaint is not due to normal engine operation. Verify that the complaint is not due to error of the operator.
- Perform a visual inspection. Inspect the following items:
- Fuel supply
- Engine oil level
- Coolant level
- Wiring and electrical connectors
For problems that are related to the electrical system, be sure to check the electrical connectors. This is specially true for problems that are intermittent.
If these inspections do not reveal any problems, identify the probable causes of the symptoms.
- Fuel supply
- Check the history of the alarms in the monitoring system. Acknowledge any active alarms. Take care of the active alarms first.
This section provides the symptoms of some possible problems. Some probable causes and recommended repairs are suggested. The service technician must determine the most likely probable causes.
All of the probable causes and recommended repairs cannot be provided. Additional work beyond the recommendations may be needed. A problem is not normally caused by a single part. Most problems involve the relationships of parts.
The probable cause of a problem only provides an indication of the location of a possible problem. Conditions such as poor fuel quality or improperly adjusted components can cause some engine symptoms.
Narrow the probable cause. Consider the operator information, the conditions of operation, and the history of the engine. Service personnel may remember similar complaints which were corrected by a previous method of troubleshooting. However, a similar complaint can have a different cause.
Obtain the following information from the operator:
- The problem and the time of the occurrence
- Determine the operating conditions for the occurrence.
- Determine if there are any systems that were installed by the customer that could cause the symptom.
- Determine whether any other symptoms happened in addition to the problem.
Note: If the problem only occurs under certain operating conditions (high idle, full load, engine operating temperature, etc), test the engine under those conditions.
If other symptoms occurred in addition to the problem, determine whether the other symptoms are related to the problem. Determine whether the symptoms and the problem have a probable cause that is common. For example, high engine oil pressure and excessive consumption of engine oil can be caused by the use of incorrect engine oil.
Report the Service Information
After you have successfully repaired the engine, it is important to provide good information about the repair. The following topics are recommended for your report:
Complaint - Include a description of the customer's complaint in the report.
Cause - Provide a specific description of the cause of the failure. Include the method that was used in order to diagnose the problem. Indicate your determination of the problem. If you performed a test, identify the test procedure. For example, a visual inspection revealed abrasion of a wire in a harness. Be specific: testing of the engine produced power below specifications at 1000 rpm due to the loss of a fuel injector.
Repair - Explain your repair of the problem. For example, you may have installed a new wiring harness. You may have replaced the fuel injector per instructions from the factory.
Providing complete, accurate information will help Caterpillar to provide better service to you and to the customer.
- Incorrect fuel injector timing
- Problem with a fuel injector
If the fuel injector timing is incorrect, the fuel will be supplied to the cylinders at the wrong time. This can cause combustion noise (knock). Make sure that the fuel injector timing is correct. Refer to Testing and Adjusting, "Fuel Injector Timing".
If a fuel injector is leaking, the fuel will be supplied to the cylinder at the wrong time. This can cause combustion noise (knock). Check the cylinders' exhaust port temperatures. A high temperature can indicate that the cylinder is receiving too much fuel. If the exhaust temperature of any cylinder has a difference of 50 °C (90 °F) from the average exhaust temperature of all of the cylinders, there may be a problem with the fuel injector. Replace the fuel injector.
- Engine oil cooler
- Cylinder liner
- Cylinder block
If coolant is leaking into the lubrication system through the engine oil cooler, replace the engine oil cooler. Change the engine oil and replace the engine oil filters.
If there is a problem with the seals for the cylinder liner, replace the seals.
If a cylinder liner is cracked, replace the cylinder liner.
If you suspect that the cylinder block is leaking, pressurize the cooling system in order to locate the leak. Inspect the cylinder block for cracks and/or other damage. If a problem is found, install a new cylinder block.
Excessive Black Smoke or Gray Smoke
- Inlet air restriction
- Excessive consumption of fuel
- Incorrect fuel injector timing
- Problem with a fuel injector
- Problem with an exhaust valve
The inlet air must be sufficient for combustion. The maximum allowable inlet air restriction is 3.75 kPa (15 inches of H2O). Replace the soot filters and check the air restriction again. If the inlet air restriction is still too high, inspect the inlet air piping for obstructions.
Refer to "Excessive Fuel Consumption".
If the fuel injector timing is incorrect, the fuel will be supplied to the cylinders before the air is sufficient for complete combustion. Make sure that the fuel injector timing is correct. Refer to Testing and Adjusting, "Fuel Injector Timing".
Check the cylinders' exhaust port temperatures. A high temperature can indicate that the cylinder is receiving too much fuel. If the exhaust temperature of any cylinder has a difference of 50 °C (90 °F) from the average exhaust temperature of all of the cylinders, there may be a problem with the fuel injector. Replace the fuel injector.
Inspect the condition of the exhaust valves. Replace any exhaust valve that is damaged.
Engine Oil in the Cooling System
- Leaking engine oil cooler core
If the engine oil is leaking into the cooling system through the engine oil cooler, replace the engine oil cooler.
Excessive Consumption of Engine Oil
- Incorrect engine oil
- Incorrect engine oil level
- Extended operation at low loads
- Excessive engine oil temperature
- External leak
- Internal leak
- Worn components
Use engine oil that is recommended and change the engine oil at the interval that is recommended by Operation and Maintenance Manual, SEBU7150.
Overfilling the crankcase will increase the consumption of engine oil. Make sure that the engine oil level is correct.
When the engine crankcase is full, engine oil will be initially consumed at a relatively rapid rate. The rate of consumption is reduced as the engine oil level decreases. A crankcase that is always maintained at the full level will have a faster rate of consumption.
If the engine has a system for automatically filling the crankcase with engine oil, check the level for the system. Adjust the system in order to provide engine oil to a level that is less than the full level. Make sure that the supply of engine oil is adequate.
Refer to "High Engine Oil Temperature".
Extended Operation with Low Loads
Extended operation at low idle or at a reduced load will cause increased consumption of engine oil. Deposits will build up in the cylinders. This will occur if the engine is usually operated at a torque that is significantly below the rated power. Do not operate the engine at low idle or low loads for extended periods.
Check for leakage at the seals at each end of the crankshaft. Look for leakage at the gasket for the engine oil pan and at all lubrication system connections. Look for any leaking from the crankcase breather. This can be caused by combustion gas leakage around the pistons. To determine the condition of the piston rings, measure the crankcase blowby.
A dirty crankcase breather will cause high pressure in the crankcase. A dirty crankcase breather will cause the gaskets and the seals to leak. Clean the crankcase breather.
Signs of internal leaks include high consumption of engine oil and blue smoke. There are several possible ways for engine oil to leak into the combustion chambers:
- Overfilling of the crankcase
- Incorrect dipstick or guide tube
- Leakage between worn valve guides and valve stems
- Leakage from the holes for plugs in the rocker arm shaft
- Pistons and/or piston rings that are worn or damaged
- Incorrect installation of the compression ring and/or the intermediate ring
- Worn cylinder liners
- Clogged passages for engine oil
- Leakage past the oil seal in the turbocharger
Thoroughly inspect any suspect components. Make the necessary repairs.
Excessively worn engine components and damaged engine components can result from the following conditions:
- Contaminated engine oil
- Contaminated fuel
- Contamination from the inlet air
- Incorrect fuel system settings
Inspect the suspect system. Make the necessary repairs.
- Fuel leak
- Poor fuel quality
- Inlet air restriction
- Exhaust restriction
- Engine overload
- Incorrect fuel injector timing
- Problem with a fuel injector
- Misfire
Inspect the fuel system for leaks. If leaks are found, make the necessary repairs.
Make sure that the fuel meets the standards that are listed in Operation and Maintenance Manual, SEBU7150, "Fuel Specifications".
The inlet air must be sufficient for combustion. The maximum allowable inlet air restriction is 3.75 kPa (15 inches of H2O). Replace the soot filters and check the air restriction again. If the inlet air restriction is still too high, inspect the inlet air piping for obstructions.
The maximum allowable exhaust back pressure is 2.5 kPa (10 inches of H2O). If the difference of the pressure at the exhaust elbow and the atmospheric pressure exceeds this specification, determine the cause. Check for restriction in the exhaust system. Make the necessary repairs.
Reduce the load. Do not operate the engine at a load that is greater than the rated load.
If the fuel injector timing is incorrect, the fuel will be supplied to the cylinders at the wrong time. This can increase fuel consumption. Make sure that the fuel injector timing is correct. Refer to Testing and Adjusting, "Fuel Injector Timing".
Check the cylinders' exhaust port temperatures. A high temperature can indicate that the cylinder is receiving too much fuel. If the exhaust temperature of any cylinder has a difference of 50 °C (90 °F) from the average exhaust temperature of all of the cylinders, there may be a problem with the fuel injector. Replace the fuel injector.
Refer to "Misfire or Rough Operation".
- Vibration damper
- Engine mounts
- Driven equipment
- Misfire and/or rough operation
- Adjacent equipment
Inspect the vibration damper for damage. Look for evidence of leaks.
Inspect the vibration damper for evidence of overheating.
Make sure that the vibration damper is fastened securely.
Inspect the condition of the engine mounts. Refer to Operation and Maintenance Manual, SEBU7150, "Engine Mounts - Inspect". Look for proper installation. Refer to Operation and Maintenance Manual, SEBU7150, "Engine Mounts - Check". Make sure that the bolts are secure.
Inspect the alignment and the balance of the driven equipment. Inspect the coupling. If necessary, disconnect the driven equipment and test the engine.
Misfire and/or Rough Operation
Refer to "Misfire or Rough Operation".
Other equipment in the engine room may be causing the vibration. Check the other equipment in the engine room.
- Cold engine
- Coolant in the combustion chamber
A cold engine will produce white smoke. The white smoke will dissipate as the engine warms up.
Coolant in the Combustion Chamber
If the coolant leaks from the aftercooler into the air inlet manifold, the coolant can flow into the combustion chamber. Inspect the aftercooler core for leaks. Make the necessary repairs.
- Low coolant level
- The cooling system is not pressurized.
- Incorrect coolant mixture
- Lack of cooling system maintenance
- High ambient temperature and/or high inlet air temperature
- Insufficient flow of air or of coolant through the heat exchanger
- Faulty water temperature regulators
- Faulty coolant temperature sensor and/or circuit
- Insufficient flow of coolant through the engine
- Exhaust restriction
- Excessive load
- Incorrect fuel injector timing
- Combustion gas in the coolant
The cooling system is designed to be pressurized for efficient operation. Aeration reduces the efficiency. Make sure that there are no air leaks. Check the filler cap for proper sealing.
Note: Low coolant level can be the effect of overheating rather than the cause.
Check the coolant level. Run the engine to operating temperature. Inspect the cooling system for leaks. Check for possible leaks at the turbocharger, the exhaust manifold, the cylinder head, and the cylinder liner.
Add coolant, if necessary. If leaking is found, make the necessary repairs.
To ensure the efficient exchange of heat, the correct coolant mixture must be used. Make sure that the water conforms to the requirements and make sure that the recommended ratio of SCA and water is maintained. Refer to Operation and Maintenance Manual, SEBU7150, "Cooling System Specifications".
Deposits and scale will build up in the cooling system if the system is not properly maintained. Change the coolant and clean the cooling system regularly. Refer to Operation and Maintenance Manual, SEBU7150, "Maintenance Interval Schedule".
High Ambient Temperature and/or High Inlet Air Temperature
Determine if the ambient air temperature is within the design specifications for the cooling system.
Check for high inlet air temperature. Refer to "High Inlet Manifold Air Temperature".
Determine the cause of the high air temperature. Make corrections, when possible.
Insufficient Flow of Coolant Through the Heat Exchanger
Check the flow of coolant through the heat exchanger. If the flow is obstructed, flush the heat exchanger.
Make sure that size of the heat exchanger is adequate.
Check the inlet temperature of the coolant. Compare the reading to the regulated temperature. If the temperature is OK, check the outlet temperature of the coolant. A low temperature differential indicates an insufficient flow rate.
- Check the water circuit for obstructions.
- Check the water pump for proper operation.
The water temperature regulators should not begin to open until jacket water reaches opening temperature for the regulators. Allow the engine to cool and then start the engine. Check the tube at the outlet for the jacket water. If the tube is warm and normal operating temperature is not achieved, a regulator may be stuck open.
Check the water temperature regulators according to Testing and Adjusting, "Water Temperature Regulator - Test". Replace the water temperature regulators, if necessary.
Coolant Temperature Sensor and/or the Circuit
Check the reading of the coolant temperature with a test thermometer. The temperature should rise steadily as the engine is warmed. Ensure that the temperature is reasonable.
Compare the reading from the test thermometer with the reading from the coolant temperature sensor. If the reading for the coolant temperature is not reasonable, troubleshoot the electrical circuit and the coolant temperature sensor.
Flow of Coolant Through the Engine
During normal operation, check the coolant pressure. Make sure that the water pumps are operating correctly.
If the flow of coolant through the engine is not sufficient, determine the cause of the obstruction. Make necessary repairs.
The maximum allowable exhaust restriction is 2.5 kPa (10 inches of H2O). Check for restriction in the exhaust system.
If the difference between the pressure at the exhaust elbow and the atmospheric pressure exceeds the specification, determine the cause. Make the necessary repairs.
Make sure that the load is not excessive. Do not operate the engine above the rated load.
If the fuel injector timing is incorrect, the combustion can be too rich. This can result in operating temperatures that are higher than normal. Make sure that the fuel injector timing is correct. Refer to Testing and Adjusting, "Fuel Injector Timing".
If combustion gas is leaking into the cooling system, look for the following conditions:
- Leaking cylinder liner seals
- Cracked cylinder liner
- Leaking seals around the valves
- Cracked cylinder head
- High engine oil level
- Plugged crankcase breather and/or ventilation system
- Plugged port on the crankcase pressure contactor
- Problem with the contactor
- Loose fuel injector
- Damaged oil seal in the turbocharger
- Internal engine problem
If the engine oil level is too high, the volume of the atmosphere in the crankcase is reduced. This can increase the crankcase pressure. Drain some of the engine oil.
A plugged crankcase breather or a plugged ventilation system for the crankcase will cause excessive crankcase pressure. Leakage of the crankshaft seal can occur. Sealing of the piston rings can be lost. This will enable crankcase blowby to further increase the crankcase pressure.
The crankcase ventilation system must have an upward slope to the atmosphere. Water must not be able to collect in the ventilation system.
Clean the crankcase breather according to Operation and Maintenance Manual, SEBU7150, "Engine Crankcase Breather - Clean".
The crankcase pressure contactor has a port in order to allow the ambient pressure into the contactor. Inspect the port for obstructions. Clean the port, if necessary.
If you suspect that the crankcase pressure contactor is faulty, replace the contactor with a contactor that is known to be good.
If the fuel injector is loose, compression will force pressure through the opening. The pressure will be forced back into the crankcase through the oil returns. Make sure that the fuel injectors are installed according to Disassembly and Assembly, RENR1333, "Fuel Injector - Install".
If the turbocharger's oil seal is damaged, boost pressure can be forced through the oil return line into the crankcase. Replace the oil seal.
If the piston rings do not seal, blowby will increase the crankcase pressure and the problem will become worse. Performance will deteriorate. The engine will have poor combustion. Deposits will build up on the pistons, on the valves, and on the cylinder heads. Downward pumping of the pistons against the increased crankcase pressure will further reduce the performance.
To determine whether the piston rings leak, measure the crankcase blowby. The typical blowby in a new engine is approximately 0.02 m3/bkW h (0.500 ft3/bhp h).
Sticking of the pistons will also increase the crankcase pressure. If the problem is not resolved, piston seizure will result.
If a problem with a piston is suspected, do not operate the engine. Remove the crankshaft inspection covers in order to inspect the cylinder liner for scoring and for scuffing. Use the barring device to move the piston to the uppermost position. Replace the piston rings and the cylinder liner, if necessary.
- Incorrect engine oil
- Problem with the engine oil pressure gauge
- Restriction in the lubrication system
- Problem with the priority valve
- Incorrect engine oil pump
Use engine oil that is recommended and change the engine oil at the interval that is recommended by Operation and Maintenance Manual, SEBU7150.
Refer to Testing and Adjusting, "Engine Oil Pressure - Test". If the engine oil pressure gauge is incorrect, install a new gauge.
Restriction In the Lubrication System
Measure the engine oil pressure at different locations in order to locate the restriction. Remove the restriction. Make repairs, if necessary.
Inspect the priority valve. Replace any parts that are damaged or worn.
If the wrong engine oil pump is installed, the pressure could be too high. Replace the engine oil pump.
- Contaminated engine oil
- High cooling system temperature
- Problem with the engine oil temperature regulators
- Problem with the engine oil temperature sensor
- Problem with the circuit for the aftercooler and engine oil cooler
- Insufficient flow of coolant or engine oil through the engine oil cooler
- Mechanical friction
Engine oil that is contaminated with another liquid can cause high engine oil temperature because the lubricating properties are reduced. High engine oil level can be an indication of contamination. Obtain an analysis of the engine oil. Determine the reason for contamination of the engine oil and make the necessary repairs. Change the engine oil and the engine oil filter. For the correct engine oil to use, refer to Operation and Maintenance Manual, SEBU7150, "Engine Oil".
Refer to "High Coolant Temperature".
Check the Engine Oil Temperature Regulators
Make sure that the engine oil temperature regulators open at the correct temperature.
Check the Engine Oil Temperature Sensor
Check the reading of the engine oil temperature on the control panel. Compare the reading to a reading from a separate device. The temperature should rise steadily as the engine is warmed.
If the reading on the control panel for the engine oil temperature is not reasonable, replace the engine oil temperature sensor.
Make sure that the heat exchanger for the engine oil cooler and for the aftercooler is operating properly. The heat exchanger must be properly sized for the ambient conditions. Check the plumbing for obstructions.
Check the Flow Through the Engine Oil Cooler
Run the engine at normal operating temperature. Determine the pressure differential for the coolant and for the engine oil between the inlet and the outlet of the engine oil cooler. For comparative data, refer to the Technical Marketing Information for the engine.
If the pressure differential between the inlet and the outlet of the engine oil cooler exceeds the data that is published for the engine, there is an insufficient flow of coolant or engine oil through the engine oil cooler. Clean the engine oil cooler.
Friction of gears and/or bearings will raise the engine oil temperature. Measure the engine oil temperature at various locations in order to locate the hot spot. Obtain an analysis of the engine oil. Make the necessary repairs.
- Problem with a thermocouple
- Incorrect valve lash
- Incorrect fuel injector timing
- Excessive load
- Exhaust restriction
- A buildup of deposits in the cylinder or internal oil leaks
- Problem with exhaust valves
- Lack of sufficient combustion air
- Excessive inlet manifold air temperature
- High coolant temperature
Check for Suspect Thermocouples
Observe the temperatures from the thermocouples after the engine is shut off.
When the engine is operating properly, the temperatures from similar locations are reduced at a similar rate. Also, the temperatures from similar locations are comparable.
If any discrepancies are found, switch the suspect thermocouple for another thermocouple. If the temperature problem follows the thermocouple, replace the thermocouple.
If the temperature problem stays at the original location of the suspect thermocouple, investigate the cause of the high temperature.
Adjust the valve lash according to Testing and Adjusting, "Valve Lash and Valve Bridge Adjustment".
If the fuel injector timing is incorrect, the rich combustion can be too hot. Make sure that the fuel injector timing is correct. Refer to Testing and Adjusting, "Fuel Injector Timing".
The excessive load will produce excessive heat. Reduce the load. Do not operate the engine above the rated load.
The engine will retain too much heat from a restricted exhaust. The maximum allowable exhaust back pressure is 2.5 kPa (10 inches of H2O). If the difference of the pressure at the exhaust elbow and the atmospheric pressure exceeds this specification, determine the cause. Check for restriction in the exhaust system. Make the necessary repairs.
Check for Deposits in the Cylinder and Check for Internal Oil Leaks
Use a borescope to inspect the cylinders. Look for the following conditions:
- Deposits on the valve seats
- Deposits on the valve faces
- Deposits on the cylinder walls that are above the upper limit of the piston stroke
- Signs of internal oil leaks
Other signs of internal oil leaks include high oil consumption and blue smoke.
Note: Excessive deposits contribute to guttering of the valves.
If excessive deposits and/or signs of internal oil leaks are found, investigate the cause of the condition. Make repairs, as needed.
Heat from an exhaust port that is always open will be excessive. Measure the suspect cylinder pressure and/or use a borescope in order to check for problems that are related to the exhaust valves.
Lack of Sufficient Combustion Air
If there is a lack of sufficient combustion air, the rich combustion can be too hot. Several conditions can cause insufficient combustion air:
- The inlet air is restricted. The maximum allowable inlet air restriction is 3.75 kPa (15 inches of H2O). Replace the soot filters and check the air restriction again. If the inlet air restriction is still too high, inspect the inlet air piping for obstructions.
- Air is leaking from the inlet air manifold prior to the cylinders. Repair the air leak.
- Exhaust is leaking prior to the turbochargers and the turbochargers cannot develop sufficient boost pressure. Repair the exhaust leak.
- There is a problem with a turbocharger. The turbocharger may be worn or another condition may prevent the turbocharger from developing sufficient boost pressure. Inspect the turbocharger and make the necessary repairs.
- The compressor bypass valve is stuck open and the inlet air is bypassing the inlet air manifold. Repair the compressor bypass valve.
Inlet Manifold Air Temperature
Refer to "High Inlet Manifold Air Temperature".
Refer to "High Coolant Temperature".
High Inlet Manifold Air Temperature
- High ambient air temperature
- High cooling system temperature
- High inlet air restriction
- Faulty inlet air temperature sensor and/or circuit
- Insufficient flow of cooling water through the aftercooler
Determine if the ambient air temperature is within the design specifications for the cooling system. Determine if the ventilation in the engine room is sufficient. Make corrections, when possible.
Refer to "High Coolant Temperature".
When inlet air pressure is low, the turbocharger works harder in order to achieve the desired inlet manifold pressure. This increases inlet air temperature.
The maximum allowable inlet air restriction is 3.75 kPa (15 inches of H2O). Replace the soot filters and check the air restriction again. If the inlet air restriction is still too high, inspect the inlet air piping for obstructions.
Check the Temperature Sensor and/or the Circuit
Allow the sensor to cool and remove the sensor. Check the reading for the inlet air temperature. If the sensor is OK, the reading and the ambient temperature are approximately equal.
If the reading is not correct, switch the sensor with a sensor that is known to be good. Verify that the problem is solved.
Check for Sufficient Flow of Cooling Water Through the Aftercooler
Check the inlet temperature of the coolant for the aftercooler. Compare the reading to the regulated temperature. If the temperature is OK, check the outlet temperature of the coolant. A high temperature differential indicates an insufficient flow rate.
Make sure that the performance of the heat exchanger is correct.
If there is a high differential between the inlet temperature and the outlet temperature of the coolant for the aftercooler, perform the following procedures:
- Check the water circuit of the aftercooler for obstructions.
- Make sure that the water temperature regulators are operating properly.
- Check the water pump for proper operation.
Make repairs, if necessary.
- Lack of scheduled maintenance
- Incorrect valve bridge adjustment
- Valve recession
- Insufficient lubrication
- Incorrect camshaft timing
- Cylinder head and related components
Adjust the valve lash and the valve bridge according to Testing and Adjusting, "Valve Lash and Valve Bridge Adjustment". Perform this maintenance regularly according to the Operation and Maintenance Manual, SEBU7150, "Maintenance Interval Schedlue".
Adjust the valve lash and the valve bridge according to Testing and Adjusting, "Valve Lash and Valve Bridge Adjustment".
Worn valves and/or valve seats will cause the valve lash to be incorrect. Inspect the valves and the valve seats. Recondition the cylinder head, if necessary.
The passages that provide engine oil to the cylinder head are particularly important. The passages must be clean. Check the lubrication in the valve compartment. There must be a greater flow of engine oil at high rpm and less flow at low rpm.
Check the camshaft timing according to Testing and Adjusting, "Camshaft Timing". Adjust the camshaft timing, if necessary.
Cylinder Head and Related Components
Inspect the valve train components. Check for signs of damage and/or wear to all of the following components:
- Valves
- Valve bridges
- Springs
- Lifters
- Rocker arms
- Pushrods
- Fuel injector
- Camshaft
Replace worn parts or damaged parts, as needed.
- Low engine oil level
- Incorrect engine oil
- Problem with the engine oil pressure gauge
- Contaminated engine oil
- Improper circulation of the engine oil
- Worn components
Check the engine oil level. The engine oil level can possibly be too far below the suction tube for the engine oil pump. The engine oil pump cannot supply enough lubrication to the engine components. If the engine oil level is low add engine oil according to the engine's Operation and Maintenance Manual, SEBU7150, "Engine Oil Level - Check".
Use engine oil that is recommended and change the engine oil at the interval that is recommended by the Operation and Maintenance Manual, SEBU7150.
Refer to Testing and Adjusting, "Engine Oil Pressure - Test". If the engine oil pressure gauge is incorrect, install a new gauge.
Engine oil that is contaminated with diesel fuel will cause low engine oil pressure. High engine oil level can be an indication of contamination. Obtain an analysis of the engine oil. Determine the reason for contamination of the engine oil and make the necessary repairs. Change the engine oil and the engine oil filters. For the correct engine oil to use, refer to Operation and Maintenance Manual, SEBU7150, "Engine Oil".
Improper Circulation of the Engine Oil
Several factors could cause improper circulation of the engine oil:
- The engine oil filter is clogged. Replace the engine oil filter.
- An engine oil line or a passage for engine oil is disconnected or broken. Repair the line or the passage.
- The engine oil cooler is clogged. Thoroughly clean the engine oil cooler.
- There is a problem with a piston cooling jet. Breakage, a restriction, or incorrect installation of a piston cooling jet will cause seizure of the piston. Inspect the piston cooling jet.
- The inlet screen of the suction tube for the engine oil pump can have a restriction. This restriction will cause cavitation and a loss of engine oil pressure. Check the inlet screen on the suction tube and remove any material that may be restricting engine oil flow.
- The suction tube is drawing in air. Check the joints of the tube for cracks or a damaged O-ring seal.
- There is a problem with the engine oil pump. Check the gears of the engine oil pump for excessive wear. Engine oil pressure is reduced by gears that have too much wear.
- The plugs for engine oil in the crankshaft are not installed correctly. Make sure that the retaining rings for the plugs are secure.
- The plugs for engine oil in the rocker shaft are not installed correctly. Make sure that the plugs are secure.
- There is a problem with supply line for engine oil to the cylinder head. Inspect the supply line behind the valve lifters.
- There is a problem with the retainer for the idler gear on the rear gear train. Verify that the retainer is secure.
Excessive clearance at the crankshaft or at the camshaft bearings will cause low engine oil pressure. Also, inspect the clearance between the rocker arm shafts and the rocker arms. Check the engine components for excessive clearance.
Obtain an analysis of the engine oil. Check the analysis for the level of wear metals in the engine oil.
- Inlet air restriction
- Exhaust restriction
- Incorrect fuel pressure
- Contaminated fuel
- High fuel temperature
- Low inlet manifold air pressure
- Excessive inlet manifold air temperature
- Incorrect valve lash
- Incorrect fuel injector timing
- Incorrect fuel setting
- Problem with a fuel injector
- Problem with the fuel control linkage
- Problem with the governor actuator
- Low compression
The inlet air must be sufficient for combustion. The maximum allowable inlet air restriction is 3.75 kPa (15 inches of H2O). Replace the soot filters and check the air restriction again. If the inlet air restriction is still too high, inspect the inlet air piping for obstructions.
The maximum allowable exhaust back pressure is 2.5 kPa (10 inches of H2O). If the difference of the pressure at the exhaust elbow and the atmospheric pressure exceeds this specification, determine the cause. Check for restriction in the exhaust system. Make the necessary repairs.
Low fuel pressure and high fuel pressure can cause the engine to malfunction.
Make sure that fuel is supplied at a sufficient pressure that is stable. Make sure that the size of the fuel supply line is sufficient. Inspect the fuel system for leaks and blockage. Look for bent fuel lines.
Inspect the fuel system components: fuel tank, fuel filters, fuel supply lines, fuel transfer pump, fuel pressure control valve and check valves. Verify that the system's components are operating correctly.
If the fuel filter differential pressure reaches 70 kPa (10 psi), replace the fuel filters.
If water is found in the fuel, the water may be entering the fuel system from a leak in the fuel cooler. Inspect the fuel cooler.
Make sure that the water separators are operating correctly.
Wax may be forming in the fuel. Cloud point is the temperature when wax is formed in the fuel. Drain the fuel tank, fuel lines and fuel manifolds. Change the fuel filter. Fill the tank with fuel that has the correct cloud point. Prime the fuel system and purge the air from the system. Some installations require the use of fuel heaters in order to ensure fuel flow. Also, the use of fuel heaters prevents filter blockage from fuel wax.
If the fuel quality is low or there is water in the fuel, remove the fuel from the fuel tank. Replace the fuel filters. Make sure that the fuel meets the standards that are listed in Operation and Maintenance Manual, SEBU7150, "Fuel Specifications".
When possible, interview the operator in order to determine if fuel quality is in question. Try to determine if the source of the fuel was changed. Obtain a fuel analysis, if necessary.
If the fuel supply temperature is 38 °C (100 °F) or more, a fuel cooler may be necessary. Return fuel serves to remove heat from the fuel injectors. A fuel cooler is recommended in order to prevent excessive power loss and a fuel cooler is recommended in order to maintain an acceptable injector life.
Low Inlet Manifold Air Pressure
Check the inlet manifold air pressure. If the pressure is too low, inspect the outlet of the turbocharger to the air inlet manifold. Check for air leaks.
Make sure that the turbocharger is operating correctly. Carbon deposits or other causes of friction such as worn bearings will reduce boost pressure. Inspect the turbocharger. Repair the turbocharger, if necessary.
If the engine is operating at an rpm that is above the setpoint for closure of the exhaust bypass, make sure that the exhaust bypass is closed.
Inlet Manifold Air Temperature
Refer to "High Inlet Manifold Air Temperature".
Adjust the valve lash according to Testing and Adjusting, "Valve Lash and Valve Bridge Adjustment".
If the fuel injector timing is incorrect, the fuel will be supplied to the cylinders at the wrong time. This can reduce power. Make sure that the fuel injector timing is correct. Refer to Testing and Adjusting, "Fuel Injector Timing".
Check the fuel setting and adjust the fuel setting, if necessary. Refer to Testing And Adjusting, "Fuel Setting".
Check the cylinders' exhaust port temperatures. A low temperature can indicate that the cylinder is not receiving fuel. A high temperature can indicate that the cylinder is receiving too much fuel. Either condition can indicate a problem with a fuel injector. If the exhaust temperature of any cylinder has a difference of 50 °C (90 °F) from the average exhaust temperature of all of the cylinders, there may be a problem with the fuel injector.
The fuel control linkage may be binding or the linkage may be worn. Inspect the linkage for binding and wear. Repair the linkage or replace the linkage, if necessary.
Inspect the linkage between the actuator and the fuel control linkage. Make sure that the actuator operates smoothly for the full range of travel. The linkage must have no free play.
If the linkage is at the maximum fuel position and the engine runs below rated speed under load, check the adjustment of the governor control. Refer to Service Manual, RENR5971, "System Operation and Programming Guide for Digital Governor Control used on 3618 Engine".
Adjust the governor actuator and the linkage, if necessary.
Low cylinder compression will reduce the power output. Check the cylinder compression. Determine the cause of the low compression and make the necessary repairs.
- Incorrect valve bridge adjustment
- Driven Equipment
- Cylinder head and related components
- Gear train
- Incorrect camshaft timing
- Crankshaft and related components
- Piston
Adjust the valve lash and the valve bridge according to Testing and Adjusting, "Valve Lash and Valve Bridge Adjustment".
Inspect the alignment and the balance of the driven equipment. Inspect the coupling. If necessary, disconnect the driven equipment and test the engine.
Cylinder Head and Related Components
Inspect the valve train components. Check for signs of damage and/or wear to all of the following components:
- Valves
- Valve bridges
- Springs
- Lifters
- Rocker arms
- Pushrods
- Fuel injector
- Camshaft
Replace worn parts or damaged parts, as needed.
Inspect the condition of the gear train. Inspect the engine oil filters for nonferrous material. Flaking of nonferrous material could indicate worn gear train bearings.
Incorrect camshaft timing can result in contact between the piston and the valves. Refer to Testing and Adjusting, "Camshaft Timing".
Crankshaft and Related Components
Inspect the crankshaft and the related components. Inspect the connecting rod bearings and the bearing surfaces on the crankshaft. Make sure that the bearings are in the correct position.
Look for worn thrust plates and wear on the crankshaft.
Check the bolts of the counterweights. Refer to the engine's Specifications, RENR1337, "Crankshaft".
Make sure that the piston pin is correctly installed.
- Inlet air restriction
- Air in the fuel system
- Contaminated fuel
- Incorrect fuel pressure
- Excessive load
- Incorrect fuel injector timing
- Problem with a fuel injector
- Problem with a fuel injector's pushrod
- Problem with a valve
- Incorrect valve lash
The inlet air must be sufficient for combustion. The maximum allowable inlet air restriction is 3.75 kPa (15 inches of H2O). Replace the soot filters and check the air restriction again. If the inlet air restriction is still too high, inspect the inlet air piping for obstructions.
If the fuel filters have been changed or if the engine has not been operated for some time, prime the fuel system. Purge the air from the fuel system.
Air may be leaking into the fuel system. The suction side of the fuel transfer pump is a possible location for air leaks. If air is leaking into the fuel system, make the necessary repairs. Prime the fuel system and purge the air from the system.
If water is found in the fuel, the water may be entering the fuel system from a leak in the fuel cooler. Inspect the fuel cooler.
Make sure that the water separators are operating correctly.
Wax may be forming in the fuel. Cloud point is the temperature when wax is formed in the fuel. Drain the fuel tank, fuel lines and fuel manifolds. Change the fuel filter. Fill the tank with fuel that has the correct cloud point. Prime the fuel system and purge the air from the system. Some installations require the use of fuel heaters in order to ensure fuel flow. Also, the use of fuel heaters prevents filter blockage from fuel wax.
If the fuel quality is low or there is water in the fuel, remove the fuel from the fuel tank. Replace the fuel filters. Make sure that the fuel meets the standards that are listed in Operation and Maintenance Manual, SEBU7150, "Fuel Specifications".
When possible, interview the operator in order to determine if fuel quality is in question. Try to determine if the source of the fuel was changed. Obtain a fuel analysis, if necessary.
Low fuel pressure and high fuel pressure can cause the engine to malfunction.
Make sure that fuel is supplied at a sufficient pressure that is stable. Make sure that the size of the fuel supply line is sufficient. Inspect the fuel system for leaks and blockage. Look for bent fuel lines.
Inspect the fuel system components: fuel tank, fuel filters, fuel supply lines, fuel transfer pump, fuel pressure control valve and check valves. Verify that the system's components are operating correctly.
If the fuel filter differential pressure reaches 70 kPa (10 psi), replace the fuel filters.
Make sure that the load is not excessive. Reduce the load in order to observe any change in the engine operation.
If the fuel injector timing is incorrect, the fuel will be supplied to the cylinders at the wrong time. Make sure that the fuel injector timing is correct. Refer to Testing and Adjusting, "Fuel Injector Timing".
Check the cylinders' exhaust port temperatures. A low temperature can indicate that the cylinder is not receiving fuel. A high temperature can indicate that the cylinder is receiving too much fuel. Either condition can indicate a problem with a fuel injector. If the exhaust temperature of any cylinder has a difference of 50 °C (90 °F) from the average exhaust temperature of all of the cylinders, there may be a problem with the fuel injector.
Make sure that the fuel injector's pushrod is in good condition. If the pushrod is bent or broken, install a new pushrod.
Check the cylinders' exhaust port temperatures. A low temperature can indicate that the inlet valves are not opening properly and air is not available for combustion. A high temperature can indicate that the exhaust valves are not closing properly. If the exhaust temperature of any cylinder has a difference of 50 °C (90 °F) from the average exhaust temperature of all of the cylinders, there may be a problem with the valves.
If a problem with a valve is suspected, measure the cylinder compression.
Adjust the valve lash according to Testing and Adjusting, "Valve Lash and Valve Bridge Adjustment".
- Incorrect valve lash
- Loose fuel injector
- Insufficient lubrication
- Cylinder head and related components
Adjust the valve lash according to Testing and Adjusting, "Valve Lash and Valve Bridge Adjustment".
Make sure that the fuel injectors are installed according to Disassembly and Assembly, RENR1333, "Fuel Injector - Install".
The passages that provide engine oil to the cylinder head are particularly important. The passages must be clean. Check the lubrication in the valve compartment. There must be a greater flow of engine oil at high rpm and less flow at low rpm.
Cylinder Head and Related Components
Inspect the valve train components. Check for signs of damage and/or wear to all of the following components:
- Valves
- Valve bridges
- Springs
- Lifters
- Rocker arms
- Pushrods
- Fuel injector
- Camshaft
Replace worn parts or damaged parts, as needed.
- Incorrect engine oil or contaminated engine oil
- Contaminated inlet air
- Contaminated fuel
- Restriction in a passage for engine oil
Use engine oil that is recommended and change the engine oil at the interval that is recommended by the Operation and Maintenance Manual, SEBU7150.
To determine whether the engine oil is contaminated, obtain an analysis of the engine oil.
If fuel leaks into the engine oil, high fuel consumption and low engine oil pressure will result. This condition may also increase the oil level in the crankcase. Make repairs if leaks are found.
Inspect the soot filters for cleanliness and good condition. Inspect the connections and the gaskets for the inlet air piping.
If water is found in the fuel, the water may be entering the fuel system from a leak in the fuel cooler. Inspect the fuel cooler.
Make sure that the water separators are operating correctly.
Wax may be forming in the fuel. Cloud point is the temperature when wax is formed in the fuel. Drain the fuel tank, fuel lines and fuel manifolds. Change the fuel filter. Fill the tank with fuel that has the correct cloud point. Prime the fuel system and purge the air from the system. Some installations require the use of fuel heaters in order to ensure fuel flow. Also, the use of fuel heaters prevents filter blockage from fuel wax.
When possible, interview the operator in order to determine if fuel quality is in question. Try to determine if the source of the fuel was changed. Obtain a fuel analysis, if necessary. Make sure that the fuel meets the standards that are listed in Operation and Maintenance Manual, SEBU7150, "Fuel Specifications".
Restriction in a Passage for Engine Oil
When some components of the engine show bearing wear in a short time, the cause can be a restriction in a passage for engine oil.
An indicator for the engine oil pressure may indicate sufficient pressure, but a component is worn due to a lack of lubrication. In such a case, look at the passage for the engine oil supply to the component.
- Slow starting motor
- Solenoid or starting circuit
- Pinion or flywheel ring gear
- Mechanical problems
The air pressure may be too low for starting. Determine the cause of the low air pressure. Make sure that the pressure regulating valve is set correctly. Inspect the air lines for leaks. Repair any leaks in the air lines.
After the starting motor's pinion is engaged, the relay valve enables a large volume of supply pressure to enter the air starting motor. Make sure that the relay valve is not stuck. Check for leaks. Check for debris in the supply line to the starting motor. Make sure that the air line is properly connected.
Check the oil level in the lubricator and adjust the lubricator according to Operation and Maintenance Manual, SEBU7150, "Air Starting Motor Lubricator Oil Level - Check".
Inspect the fitting of the lubricator to the air line. Make sure that the fitting is tight and free of leaks.
Disassemble the lubricator and clean the parts. Inspect the parts. Replace any parts that are worn or damaged or replace the lubricator.
All of the wiring for the starting circuit must be adequately sized. Check the wiring to the starting motor solenoid. Test the operation of the starting motor solenoid. If the solenoid does not operate properly, repair the solenoid or replace the solenoid.
After the starting motor's pinion is engaged, the relay valve enables a large volume of supply pressure to enter the air starting motor. Make sure that the relay valve is not stuck. Check for leaks. Check for debris in the supply line to the starting motor. Make sure that the air line is properly connected.
Inspect the pinion and the flywheel ring gear for damage. If the teeth of the pinion and/or the flywheel ring gear are worn or broken, replace the parts.
If the pinion does not engage correctly with the flywheel, look for the following conditions:
- The pinion shaft is stuck because the shaft is dry. Remove the pinion. Grease the drive shaft splines and the pinion.
- The pinion engagement piston is worn. Replace the piston and the seal.
- The pinion is installed incorrectly. Ensure that the pinion is installed for the correct rotation.
- The clutch jaws are broken. Inspect the starting motor's clutch jaws. Replace parts, if necessary.
The following conditions may not allow the pinion to disengage from the flywheel ring gear:
- The air pressure is too high. Check the air supply pressure and the air pressure regulator.
- The crank termination is incorrect. Refer to Testing and Adjusting, "Engine Speed Switch - Calibrate".
- The bearings in the air starting motor are worn. Check the condition of the bearings. Replace the bearings, if necessary.
If the pinion engages the flywheel but the flywheel does not turn, there may be a problem with the starting motor. If the starting motor turns but the flywheel does not turn, inspect the starting motor's clutch jaws, and/or other parts.
Before you remove the starting motor, use the barring device to turn the crankshaft. Ensure that a mechanical failure inside the engine is not preventing the crankshaft from turning. If the barring device will turn the crankshaft, try the starting motor again. If the starting motor does not turn the crankshaft, remove the starting motor. Inspect the starting motor for worn parts.
Check the starting motor for worn seals. Plug the starting motor's exhaust outlet and attach a source of pressurized air to the inlet. Submerge the starting motor in water for a minimum of 30 seconds. If bubbles rise from the starting motor, replace the seals.
If a vane is cracked or if the height of a vane is less than 32 mm (1.25 inch), install new vanes.
If any of the rotor bearings are loose or rough, replace the bearings.
If the rotor's body is scored, try to smooth the body with emery cloth. If the body cannot be smoothed with emery cloth, replace the rotor.
If the end plate is scored, use emery cloth to smooth the end plate.
If the cylinder is cracked or if the cylinder is scored deeply, replace the cylinder.
The Engine Cranks but the Engine Does Not Start
- Slow starting motor
- Cold engine
- Inlet air restriction
- Electrical connectors or power supply
- Fuel supply
- Incorrect fuel injector timing
- Fuel shutoff cylinders
- Engine speed sensor
- Governor and actuator
- Excessive load
Refer to "Starting Motor".
If the engine is too cold, the engine may not start. Refer to Application and Installation Guide, LEKM2005, "Starting Air".
The inlet air must be sufficient for combustion. The maximum allowable inlet air restriction is 3.75 kPa (15 inches of H2O). Replace the soot filters and check the air restriction again. If the inlet air restriction is still too high, inspect the inlet air piping for obstructions.
Electrical Connectors or Power Supply
There may be an intermittent interruption of power to the starting motor solenoid. Check the wiring harnesses and the connectors. Inspect the connectors in the terminal box. Inspect the battery connections and the ground.
Inspect the wires and the power relay for the starting motor's solenoid. Check the power and ground connections to the control panel.
If the fuel filters have been changed or if the engine has not been operated for some time, prime the fuel system. Purge the air from the fuel system.
Make sure that fuel is supplied at a sufficient pressure that is stable. Make sure that the size of the fuel line is sufficient. Inspect the fuel system for leaks and for blockage. Look for bent fuel lines.
If air is leaking into the fuel system, inspect the suction side of the fuel transfer pump. Make the necessary repairs. Prime the fuel system and purge the air from the system.
If water is found in the fuel, the water may be entering the fuel system from a leak in the fuel cooler. Inspect the fuel cooler.
When possible, interview the operator in order to determine if fuel quality is in question. Try to determine if the source of the fuel was changed. Obtain a fuel analysis, if necessary.
Inspect the fuel system components: fuel tank, fuel filters, fuel supply lines, fuel transfer pump, fuel pressure control valve and check valves. Verify that the system's components are operating correctly.
If the fuel injector timing is incorrect, the fuel will be supplied to the cylinders at the wrong time. This can prevent start-up. Make sure that the fuel injector timing is correct. Refer to Testing and Adjusting, "Fuel Injector Timing".
If a fuel shutoff cylinder is activated, the engine will not start. Make sure that the fuel shutoff cylinders are not activated.
Note: The engine has a primary speed sensor and a backup speed sensor for the governor control.
If the governor does not receive a signal from the speed sensor, the engine will not start.
Observe the governor's indicator for the sensor. The indicator is red when the engine is stopped. If the indicator stays illuminated during cranking, the governor is not receiving a signal from the sensor.
Make sure that the engine speed sensor is installed in the flywheel housing according to the engine's Specifications. Make sure that the wiring and the electrical connections are in good condition.
If everything appears to be in good condition, switch the suspect speed sensor for a sensor that is known to be good.
Observe the governor control's indicator for the actuator. The indicator is normally off when the engine is stopped. If the indicator is illuminated but the engine is stopped, there is a problem with the wiring harness to the actuator or there is a problem with the actuator.
Crank the engine and observe the governor's indicators. The indicator for the speed sensor will be extinguished. The indicator for the actuator will illuminate. If this happens and the engine does not start check the actuator's output shaft for movement. Verify that the actuator is properly calibrated. Refer to Service Manual, RENR5971, "System Operation and Programming Guide for Digital Governor Control used on 3618 Engine". Inspect the wiring and the electrical connections.
Inspect the linkage between the actuator and the fuel control linkage. Make sure that the actuator operates smoothly for the full range of travel. The linkage must have no free play. Adjust the governor control, the actuator, and the linkage, if necessary.
Make sure that the load is not excessive. Reduce the load. If necessary, disengage the driven equipment and test the engine.
The Engine Overspeeds On Start-up
- Incorrect calibration of the engine speed switch
- Problem with the fuel control linkage
- Problem with the governor control
The setpoint for engine overspeed may be too low. Calibrate the engine speed switch according to Testing and Adjusting, "Engine Speed Switch - Calibrate".
Inspect the fuel control linkage for the following conditions:
- Incorrect assembly after overhaul
- Binding of the fuel control linkage
- Incorrect adjustment of the actuator's output lever
Make the necessary repairs.
The engine can overspeed if the governor control is not correctly adjusted. Adjust the governor control according to Service Manual, RENR5971, "System Operation and Programming Guide for Digital Governor Control used on 3618 Engine".
- Incorrect low idle setting
- Excessive load
- Fuel supply
- Problem with a fuel injector
Adjust the governor control's low idle setting. Ensure that the low idle rpm matches the rpm that is specified for the engine's Technical Marketing Information. Adjust the governor control according to Service Manual, RENR5971, "System Operation and Programming Guide for Digital Governor Control used on 3618 Engine".
Reduce the load. If necessary, disengage the driven equipment and test the engine.
If the fuel filters have been changed or if the engine has not been operated for some time, prime the fuel system. Purge the air from the fuel system.
Make sure that fuel is supplied at a sufficient pressure that is stable. Make sure that the size of the fuel line is sufficient. Inspect the fuel system for leaks and for blockage. Look for bent fuel lines.
If air is leaking into the fuel system, inspect the suction side of the fuel transfer pump. Make the necessary repairs. Prime the fuel system and purge the air from the system.
If water is found in the fuel, the water may be entering the fuel system from a leak in the fuel cooler. Inspect the fuel cooler.
Make sure that the water separators are operating correctly.
When possible, interview the operator in order to determine if fuel quality is in question. Try to determine if the source of the fuel was changed. Obtain a fuel analysis, if necessary.
Inspect the fuel system components: fuel tank, fuel filters, fuel supply lines, fuel transfer pump, fuel pressure control valve and check valves. Verify that the system's components are operating correctly.
Check the cylinders' exhaust port temperatures. A low temperature can indicate that the cylinder is not receiving fuel. If the exhaust temperature of any cylinder has a difference of 50 °C (90 °F) from the average exhaust temperature of all of the cylinders, there may be a problem with the fuel injector.
- Engaged barring device
- Static load
- Start/stop controls
- Electrical system or interlocks
- Problem with the starting motor
- Prelube pressure
- Fluid in the cylinder
- Internal mechanical problem
The engine will not crank if the barring device is even slightly engaged. Make sure that the barring device is completely disengaged.
Make sure that the clutch is disengaged. Make sure that any other equipment that is driven by the engine is not preventing the crankshaft from turning. Attempt to turn the crankshaft with the barring device. If necessary, disengage the driven equipment and test the engine.
Make sure that an emergency stop button is not engaged and reset the control system.
Check the engine control switch for proper operation. Make sure that the contacts are correct when the switch is in different positions.
Electrical System or Interlocks
Check the power supply for the control panel. Make sure that the voltage is not interrupted.
Interlocks for the clutch, the prelube, and any other customer supplied interlocks can prevent start-up. Check the relays for proper operation.
Inspect the electrical connectors for loose connections and corrosion. Inspect the harnesses for wiring that is pinched, frayed, or otherwise damaged. Make sure that the insulation is good. Tighten any loose connections. Make repairs, if necessary.
Problem with the Starting Motor
Refer to "Starting Motor".
If prelube pressure is not achieved, the engine will not crank.
The prelube pump's solenoid may have an open circuit or a short circuit. The prelube pump's motor may have an electrical problem. Inspect the electrical circuit of the prelube pump's pressure switch. Inspect the wiring for good condition and secure connections. Repair the wiring or replace the wiring.
Check the prelube pump's pressure switch for proper operation. Remove the prelube pump's pressure switch. Measure the resistance between the switch's terminals. Then apply 9 ± 3 kPa (1.3 ± 0.4 psi) of pressure to the switch and measure the resistance between the terminals again. If the switch is operating correctly, the switch is open with no pressure and the switch closes with 9 ± 3 kPa (1.3 ± 0.4 psi) of pressure. If there is a problem with a switch, replace the switch.
There may be a mechanical problem with the prelube pump. Repair the pump or replace the pump.
Open the manual valves (if equipped). If the engine does not have manual valves, remove the cylinder pressure relief valves or the plugs. Keep all personnel away from the ports and use the barring device to rotate the crankshaft. Check for evidence of fluid from the ports.
If fluid is found, determine the type of fluid.
If the fluid is fuel, there is probably a problem with the fuel injector.
If the fluid is coolant, there is probably a leak in the cylinder head. A seal or a gasket for a cylinder liner may be leaking.
If the crankshaft will not turn and the driven equipment is disengaged, check for fluid in the cylinders. If this is not the problem, the engine must be disassembled in order to investigate internal mechanical problems. Possible internal problems include the following conditions:
- Bearing seizure
- Piston seizure
- Valve and piston contact
- Damage to the crankshaft
The Governor Cannot Shut Down the Engine
- Incorrect governor control adjustment
- Problem with the fuel control linkage
- Problem with the governor's actuator
The governor cannot properly shut down the engine if the governor control is not correctly adjusted. Adjust the governor control according to Service Manual, RENR5971, "System Operation and Programming Guide for Digital Governor Control used on 3618 Engine".
The fuel control linkage may be binding or the linkage may be worn. Inspect the linkage for binding and for wear. Repair the linkage or replace the linkage, if necessary.
The governor actuator may be incorrectly installed. Ensure that the actuator's terminal shaft is engaged correctly with the fuel control linkage stop lever.
The actuator may require service. Replace the actuator, if necessary.
- Contaminated fuel
- Problem with the speed sensor
- Problem with the fuel control linkage
- Problem with the governor control
- Seizure of the fuel injector
If water is found in the fuel, the water may be entering the fuel system from a leak in the fuel cooler. Inspect the fuel cooler.
Make sure that the water separators are operating correctly.
Wax may be forming in the fuel. Cloud point is the temperature when wax is formed in the fuel. Drain the fuel tank, fuel lines and fuel manifolds. Change the fuel filter. Fill the tank with fuel that has the correct cloud point. Prime the fuel system and purge the air from the system. Some installations require the use of fuel heaters in order to ensure fuel flow. Also, the use of fuel heaters prevents filter blockage from fuel wax.
If the fuel quality is low or there is water in the fuel, remove the fuel from the fuel tank. Replace the fuel filters. Make sure that the fuel meets the standards that are listed in Operation and Maintenance Manual, SEBU7150, "Fuel Specifications".
When possible, interview the operator in order to determine if fuel quality is in question. Try to determine if the source of the fuel was changed. Obtain a fuel analysis, if necessary.
Inspect the speed sensor. If metal particles are on the magnet, clean the magnet. Make sure that the speed sensor is installed according to Specifications, RENR1337, "Electronic Sensors".
Inspect the wiring and electrical connections for the speed sensor. Make repairs, if necessary.
Inspect the flywheel ring gear for broken teeth.
The fuel control linkage may be binding or the linkage may be worn. Inspect the linkage for binding and wear. Repair the linkage or replace the linkage, if necessary.
The engine operation can be unstable if the governor control is not correctly adjusted. The governor control's gain may require adjustment. Adjust the governor control according to Service Manual, RENR5971, "System Operation and Programming Guide for Digital Governor Control used on 3618 Engine".
Check the cylinders' exhaust port temperatures. A low temperature can indicate that the cylinder is not receiving fuel. If the exhaust temperature of any cylinder has a difference of 50 °C (90 °F) from the average exhaust temperature of all of the cylinders, there may be a problem with the fuel injector. For injector seizure, replace the fuel injector.