3126 HEUI Industrial Engine Caterpillar

Introduction

Troubleshooting can be difficult. The following pages contain a list of possible problems. In order to make a repair to a problem, refer to the cause and the correction of the problem.

The list on the following pages will provide the following information:

• known problems

• probable causes of known problems

• repairs in order to correct known problems

Normally, additional repair work is needed beyond the recommendation in the list.

Remember that a problem is not normally caused by only one part. The problem's cause can be related to problems with other parts. This list does not include all possible problems and corrections. The service technician must find the problem and the problem's source. After the problem's source is determined, the service technician can make the necessary repairs.

Troubleshooting Problem List

1. The Engine Crankshaft Will Not Turn When The Start Switch Is Switched On.

2. The Engine Is Difficult To Start Or The Engine Will Not Start. The Engine Crankshaft Turns Too Slowly.

3. The Engine Cranks But The Engine Will Not Start. The Engine Crankshaft Turns Freely.

4. The Engine Is Misfiring Or The Engine Is Running Rough.

5. The Engine Stalls At Low RPM.

6. The Engine Does Not Have Enough Power.

7. The Engine Has Too Much Vibration.

8. The Engine Has A Loud Combustion Noise (Knock).

9. The Engine Has A Valve Train Noise (Clicking).

10. Oil Is In The Cooling System.

11. Mechanical Noise (Knock) Is In The Engine.

12. Fuel Consumption Is Too High.

13. A Loud Noise Is In The Valve Train.

14. Too Much Valve Clearance Is Present.

15. Little Valve Clearance Or No Valve Clearance Is Present.

16. Oil Is At The Exhaust.

17. The Engine Has Early Wear.

18. Coolant Is In The Lubrication Oil.

19. Too Much Black Exhaust Smoke Or Gray Exhaust Smoke Is Present.

20. Too Much White Exhaust Smoke Or Blue Exhaust Smoke Is Present.

21. The Engine Has Low Oil Pressure.

22. The Engine Uses Too Much Lubrication Oil.

23. The Engine Coolant Temperature Is High.

24. The Engine Coolant Temperature Is Low.

25. The Exhaust Temperature Is Too High.

26. The Starting Motor Does Not Turn.

27. The Alternator Gives No Charge.

28. The Alternator Charge Rate Is Low Or The Alternator Charge Rate Is Not Regular.

29. The Alternator Charge Rate Is Too High.

30. The Alternator Has Noise.

31. Fuel Is In The Lubrication Oil.

32. Fuel Is In The Coolant.

33. The Engine Is Losing Coolant.

34. Soot Is In The Inlet Manifold.

35. Air Is In The Fuel.

Troubleshooting Problems

Problem 1

The Engine Crankshaft Will Not Turn When The Start Switch Is On.

Probable Cause

1. Low Output Of The Battery

   Check the condition of the battery. Charge the battery or replace the battery, as required. Refer to "Problem 28" .

2. Defective Wires Or Defective Switches

   Inspect all cables and inspect all connections. Clean connections. Tighten connections. Replace parts, as needed.

   Replace the wires or replace the switch, as needed.

3. Defective Starter Motor Solenoid

   Install a new solenoid.

4. Problem With The Starting Motor

   Refer to "Problem 26" .

5. An Internal Problem Prevents The Turning Of The Engine Crankshaft.

   If the crankshaft cannot be turned after disconnecting the driven equipment, inspect the cylinders for fluid while the crankshaft is being turned. If fluid in the cylinders is not the problem, the engine must be disassembled. After disassembling the engine, inspect the engine for other internal problems. Possible internal problems include the following conditions:

   • bearing seizure

   • piston seizure

   • valve and piston contact

6. Problem With Accessory Equipment

   Check the driveline for free movement. Disconnect the PTO drives or remove the PTO drives. Remove engine accessories and inspect engine accessories that may lock up the engine. The following components should be inspected:

   • air compressor

   • power steering pump

   • engine oil pump

   • hydraulic oil pump

Problem 2

The Engine Is Difficult To Start Or The Engine Will Not Start. The Engine Crankshaft Turns Too Slowly.

Probable Cause

1. A Slow Turning Starter Motor

   Refer to "Problem 27" and refer to "Problem 28" .

2. Low Output Of The Battery

   Check the condition of the battery. Charge the battery or replace the battery, as required. Refer to "Problem 27" and refer to "Problem 28" .

3. Incorrect Lubrication Oil

   Use the recommended lubrication viscosities that are listed in the Operation and Maintenance Manual .

4. An Internal Problem Prevents The Turning Of The Engine Crankshaft.

   Refer to "Problem 1" .

5. Problem With Accessory Equipment

   Refer to "Problem 1" .

Problem 3

The Engine Cranks But The Engine Will Not Start. The Engine Turns Freely.

Exhaust Smoke Cannot Be Seen When The Engine Is Cranked.

Probable Cause

1. Low Fuel Supply

   Check the fuel supply in order to ensure that there is sufficient fuel for engine operation.

2. Low Engine Oil Supply

   Check the level of the engine oil in order to ensure that it is correct. Engine oil is necessary to operate the high pressure oil pump. The pump supplies the high pressure oil that is used by the fuel injectors.

3. No Power To The ECM

   Check for logged codes or active diagnostic codes with the electronic service tool. Refer to Electronic Troubleshooting, "Electrical Power Supply To The ECM" for information on checking the voltage to the ECM. Check for the presence of aftermarket engine shutdown devices. These devices usually interrupt power to the ECM. Ensure that any aftermarket devices are installed correctly.

4. Missing Personality Module Software

   Check for logged codes or active diagnostic codes with the electronic service tool. The Personality Module that is in a new ECM is not programmed. If the ECM has been replaced, the ECM will not communicate with the engine. The software must be installed in the Personality Module before the engine will start.

5. No Signal From The Speed/Timing Sensor

   Crank the engine and observe the engine rpm on the status screen of the electronic service tool.

6. Incorrect Injection Actuation Pressure

   Check the dipstick in order to ensure that the oil level is normal. Check for air in the system. After working on the high pressure oil system, air may remain in the system. To purge the air, crank the engine for thirty seconds at a time at least three times. Allow the starting motor to cool for two minutes between cranking periods. Ensure that oil is reaching the inlet of the hydraulic pump. Inspect the oil supply line from the oil manifold to the inlet of the pump. Check the engine oil pressure with an oil pressure indicator. Connect the oil pressure indicator to the main oil manifold on the left side of the engine block. The oil pressure should be about 28 kPa (4 psi) to 55 kPa (8 psi) while the engine is cranking. If there is not any oil pressure, check the engine oil pump. Also check for dilution of the oil which will lower the oil pressure.

Exhaust Smoke Can Be Seen When The Engine Is Cranked.

Probable Cause

1. Dirty Fuel Filter

   Install a new fuel filter.

2. Dirty Fuel Line Or Broken Fuel Line

   Clean the fuel lines or install new fuel lines, as required.

3. Fuel Transfer Pump

   At the starting rpm, the minimum fuel pressure from the fuel transfer pump must be 275 kPa (40 psi). Change the fuel filter element if the fuel pressure is less than 275 kPa (40 psi). Look for air in the fuel system. Refer to "Air In The Fuel". Install a new fuel transfer pump if the fuel pressure is still low.

4. No Fuel To Cylinders

   Put fuel in the tank. Remove the air and/or remove the low quality fuel from the fuel system. Prime the fuel system.

5. Low Quality Fuel

   Remove the fuel from the fuel tank. Install a new fuel filter element. Fill the fuel tank with a good grade of clean fuel.

6. Loss Of Compression

   Check valve clearance and make adjustments, if necessary. Refer to "Problem 35". Low compression can also result from any of the following conditions:

   • defective head gasket

   • defective piston ring

   • incorrectly installed parts

Problem 4

The Engine Is Misfiring Or The Engine Is Running Rough.

Probable Cause

1. Low Fuel Pressure

   Check fuel pressure with the 1U-5470 Engine Pressure Group . At low idle, the fuel pressure should be between 400 kPa (58 psi) and 435 kPa (63 psi). During normal operating conditions under load, the fuel pressure should be between 400 kPa (58 psi) and 525 kPa (76 psi). Measure the fuel pressure at the inlet to the secondary fuel filter. Fuel pressure at the cylinder head fuel gallery should also be 400 kPa (58 psi) and 525 kPa (76 psi) minus the pressure differential across the secondary fuel filter. Pressure drop across the secondary fuel filter is typically at least 35 kPa (5 psi) with a new filter. As the filter accumulates deposits the pressure differential will increase. If fuel pressure at the unit injectors drops to approximately 69 kPa (10 psi) it is possible that misfires will occur. This would typically have a random effect on all cylinders, rather than a consistent misfire on a given cylinder.

   Ensure that there is fuel in the fuel tank. Look for leaks or bends in the fuel line between the fuel tank and the fuel transfer pump. Look for air in the fuel system. Also look for a defective return fuel pressure regulating valve.

   Check the fuel filters and check the fuel lines for restrictions. Check for fuel transfer pump failure. Check for damaged injector sleeves. Check the orifice check valve for looseness. Ensure that the proper orifice check valve is installed in fuel return line. Replace any damaged O-rings or damaged injector sleeves. Refer to Special Instruction, SEHS9120, "Using the 127-3458 Sleeve Replacement Tool Group" .

2. Air In Fuel System

   Find the air leak in the fuel system and correct the air leak. If there is air in the fuel system, the air generally enters the fuel system on the suction side of the fuel transfer pump. Refer to "Problem 35" .

3. Leakage Or Breakage In Fuel Line Between Fuel Manifold And Cylinder Head

   Install a new fuel line.

4. Wrong Valve Clearance

   Make an adjustment to the valve clearance. Refer to Testing And Adjusting, "Air Inlet And Exhaust System" .

5. Defect In Fuel Injector

   Check for logged diagnostic codes or active diagnostic codes with the electronic service tool. Refer to Electronic Troubleshooting for more information on the injectors.

   An injector may fail to operate properly. This will cause a misfire in that cylinder. Possible causes include the following items:

   • debris in the oil supply

   • incorrect removal of an injector

   • mechanical pressure on the solenoid

   • a shorted solenoid coil

   • an open solenoid coil

6. Loss Of Signal From A Sensor

   Momentary loss of a signal from a sensor may cause a brief drop in the engine rpm. This may be wrongly seen as an engine problem.

7. Loss Of Compression

   Check valve clearance and make adjustments, if necessary. Refer to Testing And Adjusting, "Air Inlet And Exhaust System". Low compression can also result from any of the following conditions:

   • defective head gasket

   • defective piston ring

   • incorrectly installed parts

Problem 5

The Engine Stalls At Low RPM.

Probable Cause

1. Low Fuel Pressure

   Refer to "Problem 4" .

2. Problem With Accessory Equipment

   Refer to "Problem 1" .

3. Defect In Unit Injector

   Check for logged diagnostic codes or active diagnostic codes with the electronic service tool. Refer to Electronic Troubleshooting for more information on the injectors. Also, refer to "Problem 4" .

4. Air In Fuel System

   Refer to "Problem 35" .

5. Incorrect Grade Of Fuel

   Check the grade of fuel. When the temperature is below 0.0°C (32°F) use a winter blend of fuel. Check for waxing in the fuel.

6. Low Quality Fuel

   Remove the fuel from the fuel tank. Install a new fuel filter element. Fill the fuel tank with a good grade of clean fuel.

7. Incorrect Injection Actuation Pressure

   Refer to "Problem 3" .

Problem 6

The Engine Does Not Have Enough Power.

Probable Cause

1. Dirty Fuel Filters

   Install new fuel filters.

2. Low Quality Fuel Or Water In Fuel

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

3. Low Fuel Pressure

   Refer to "Problem 4" .

4. Defect In A Unit Injector

   Check for logged diagnostic codes or active diagnostic codes with the electronic service tool. Refer to Electronic Troubleshooting for more information on the injectors. Also, refer to "Problem 4" .

5. Leaks In Air Inlet System

   Check the pressure in the air inlet manifold. Look for restrictions in the air cleaner.

6. Wrong Valve Clearance

   Make an adjustment to the valve clearance. Refer to Testing And Adjusting, "Air Inlet And Exhaust System" .

7. Excessive Engine Oil

   Remove the dipstick and check the oil level. If oil level is too high, drain some oil in order to bring the oil level to the desired level.

   Note: An oil analysis should be done in order to determine if the oil level is increasing due to a fuel leak or due to other engine problems.

8. Plugged Muffler Or Damaged Muffler

   Catalytic mufflers are susceptible to plugging. Catalytic mufflers are more susceptible to plugging if the engine is allowed to idle for long periods of time. Operating the engine in cooler climates also increases the possibility that the muffler will become plugged. One indication of a plugged muffler is poor engine response. For testing procedures on mufflers, refer to Testing And Adjusting, "Restriction Of Air Inlet And Exhaust". For information concerning the replacement of the muffler, refer to the Disassembly And Assembly Manual.

9. Defect In Aftercooler

   Check temperature of inlet and outlet coolant supply. Remove any external restrictions or internal restrictions.

10. Carbon Deposits On Turbocharger Or Other Causes Of Friction

    Inspect the turbocharger. Repair the turbocharger, if necessary.

Problem 7

The Engine Has Too Much Vibration.

Probable Cause

1. Loose Vibration Damper Or Loose Pulley

   Inspect the vibration damper for damage. Inspect the pulley for damage. Tighten the bolts, if necessary. Tighten the nuts, if necessary.

2. Defective Vibration Damper Or Defective Pulley

   Install a new vibration damper, if necessary. Install a new pulley, if necessary.

3. Loose Engine Supports Or Defective Engine Supports

   Tighten all mounting bolts. Install new components, if necessary.

4. Engine Misfiring

   Refer to "Problem 4" .

5. Unbalanced Fan Blade

   Loosen the fan drive belts or remove the fan drive belts. Operate the engine for a short time at the rpm that caused the vibration. If vibration is not present, replace the fan assembly.

Problem 8

The Engine Has A Loud Combustion Noise (Knock).

Probable Cause

1. Low Quality Fuel

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

2. Defect In A Unit Injector

   Check for logged diagnostic codes or active diagnostic codes with the electronic service tool. Refer to Electronic Troubleshooting for more information on the injectors. Also, refer to "Problem 4" .

3. Mechanical Problem

   Find the problem and correct the problem. Possible problems include the following items:

   • incorrect valve adjustment

   • sticking valve

   • internal mechanical problem

Problem 9

The Engine Has A Valve Train Noise (Clicking).

Probable Cause

1. Damage To Valve Train Components

   Inspect all of the following valve train components:

   • valves

   • springs

   • camshaft

   • lifters

   • rocker arms

   • pushrods

   Check for worn parts or damaged parts. Replace worn parts or damaged parts, as required.

2. Not Enough Lubrication

   Check the lubrication in the valve compartment. There must be a strong flow of oil at engine high rpm. There must be a small flow of oil at low rpm. Oil passages must be clean. The oil passages that send the oil to the cylinder head are particularly important.

3. Too Much Valve Clearance

   Make an adjustment to the valve clearance. Refer to Testing And Adjusting, "Air Inlet And Exhaust System" .

Problem 10

Oil Is In The Cooling System.

Probable Cause

1. Defect In Core Of Engine Oil Cooler

   Inspect each engine oil cooler. Repair any defective oil cooler or replace any defective oil cooler, as required.

2. Failure Of The Cylinder Head Gasket

   Check the cylinder head gasket. Start the engine and remove the radiator cap. Look for air bubbles in the coolant. Air bubbles are an indication of a faulty cylinder head gasket. Replace the cylinder head gasket, if necessary.

Problem 11

Mechanical Noise (Knock) Is In The Engine.

Probable Cause

1. Failure Of The Connecting Rod Bearing

   Inspect the bearings for the connecting rods and the bearing surfaces (journals) on the crankshaft. Install new parts, as required.

2. Damaged Timing Gears

   Inspect the timing gears. Install new parts, as required.

3. Damaged Crankshaft

   Replace the crankshaft.

4. Defect In Accessory Equipment

   Repair the defective components or install new components.

Problem 12

Fuel Consumption Is Too High.

Probable Cause

1. Fuel System Leaks

   Tighten the parts at points of leakage. Replace the parts, if necessary.

2. Fuel And Combustion Noise (Knock)

   Refer to "Problem 8" and "Problem 11" .

3. Low Quality Fuel

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

4. Defect In A Unit Injector

   Check for logged diagnostic codes or active diagnostic codes with the electronic service tool. Refer to Electronic Troubleshooting for more information on the injectors. Also, refer to "Problem 4" .

5. Defect In The Turbocharger

   Ensure that the turbocharger shaft spins freely. Repair the turbocharger, if necessary. Replace defective components.

Problem 13

A Loud Noise Is In The Valve Train.

Probable Cause

1. Damage To Valve Springs

   Replace any damaged parts.

2. Damage To Camshaft

   Replace any damaged parts. Clean the engine thoroughly. If a replacement of the camshaft is made, new valve lifters are also required.

3. Damage To Valve Lifter

   Replace any damaged parts. Clean the engine thoroughly. Inspect the camshaft cams (lobes) for damage. Inspect the valves that do not move freely. Make an adjustment to the valve clearance. Refer to Testing And Adjusting, "Air Inlet And Exhaust System" .

Problem 14

Too Much Valve Clearance Is Present.

Probable Cause

1. Not Enough Lubrication

   Check the lubrication in the valve compartment. There must be a strong flow of oil at engine high rpm. There must be a small flow of oil at low rpm. Oil passages must be clean. The oil passages that send the oil to the cylinder head are particularly important.

2. Worn Rocker Arm

   If the face of the rocker arm that makes contact with the valve has too much wear, install new parts or rocker arms. Make adjustment to valve clearance. Refer to Testing And Adjusting, "Air Inlet And Exhaust System" .

3. Worn Valve Stem

   If the end of the valve stem has too much wear, install new valves. Make adjustment to valve clearance. Refer to Testing And Adjusting, "Air Inlet And Exhaust System" .

4. Worn Pushrods

   If the pushrods have too much wear, install new pushrods. Make adjustment to valve clearance. Refer to Testing And Adjusting, "Air Inlet And Exhaust System" .

5. Broken Valve Lifters Or Worn Valve Lifters

   Install new valve lifters. Check the camshaft for wear. Check for free movement of valves or bent valve stem. Clean the engine thoroughly. Make adjustment to valve clearance. Refer to Testing And Adjusting, "Air Inlet And Exhaust System" .

6. Worn Camshaft

   Check valve clearance. Check for wear on camshaft lobes. Check for free movement of valves or bent valve stems. Install a new camshaft. Install new valve lifters. Make adjustment to valve clearance. Refer to Testing And Adjusting, "Air Inlet And Exhaust System" .

Problem 15

Little Valve Clearance Or No Valve Clearance Is Present.

Probable Cause

1. Worn Valve Seat Or Worn Valve Face

   Reconditioning of the cylinder head is required. Make adjustment to valve clearance. Refer to Testing And Adjusting, "Air Inlet And Exhaust System" .

Problem 16

Oil Is At The Exhaust.

Probable Cause

1. Failed Turbocharger Seals

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

2. Worn Valve Guides

   Reconditioning of the cylinder head is required.

3. Worn Piston Rings

   Inspect piston rings and install new parts, as required.

4. Scored Cylinder Walls Or Worn Cylinder Walls

   Inspect the cylinder walls for problems. Hone the cylinder walls in order to remove the scoring. If necessary, bore the cylinder walls and install sleeves.

Problem 17

The Engine Has Early Wear.

Probable Cause

1. Dirt In Lubrication Oil

   Remove dirty lubrication oil. Install new filter elements. Put clean oil in the engine.

2. Air Inlet Leaks

   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, as required.

4. Incorrect Lubrication Oil

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

5. Incorrect Maintenance Interval For The Application

   Review the oil change intervals in relation to the nature and severity of the engine application. Review the records for the engine in order to verify that the recommended intervals are being followed.

Problem 18

Coolant Is In The Lubrication Oil.

Probable Cause

1. Failure Of The Engine Oil Cooler

   Install a new engine oil cooler. Drain the crankcase and refill the crankcase with clean lubricant. Install new oil filter elements.

2. Failure Of Cylinder Head Gasket

   Check the cylinder head gasket. Start the engine and remove the radiator cap. Look for air bubbles in the coolant. Air bubbles are an indication of a faulty cylinder head gasket. Replace the cylinder head gasket, if necessary.

3. Crack Or Defect In Cylinder Head

   Install a new cylinder head.

4. Crack Or Defect In Cylinder Block

   Install a new cylinder block.

5. Failure Of The Seal Between The Cylinder Head And The Sleeve In The Unit Injector Bore

   Replace the sleeve. Refer to Special Instruction, SEHS9120, "Using the 127-3458 Sleeve Replacement Tool" for information on replacing unit injector sleeves.

Problem 19

Too Much Black Exhaust Smoke Or Gray Exhaust Smoke Is Present.

Probable Cause

1. Not Enough Air For Combustion

   Check the air cleaner for restrictions. Check the inlet manifold pressure. Inspect the turbocharger for correct operation.

2. Low Quality Fuel

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

3. Defect In A Unit Injector

   Check for logged diagnostic codes or active diagnostic codes with the electronic service tool. Refer to Electronic Troubleshooting for more information on the injectors. Also, refer to "Problem 4" .

4. Incorrect Valve Adjustment

   Make an adjustment to the valve clearance. Refer to Testing And Adjusting, "Air Inlet And Exhaust System" .

5. Incorrect Injection Actuation Pressure

   Refer to "Problem 3" .

6. Defective Boost Sensor

   Check for logged diagnostic codes or active diagnostic codes with the electronic service tool. Refer to Electronic Troubleshooting, "Excessive Black Smoke" for further information.

Problem 20

Too Much White Exhaust Smoke Or Blue Exhaust Smoke Is Present.

Probable Cause

1. Too Much Lubrication Oil In Engine

   Remove extra oil. Find the source of the extra oil. Put the correct amount of oil in engine.

2. The Engine Is Misfiring Or The Engine Is Running Rough.

   Refer to "Problem 4" .

3. Defect In A Unit Injector

   Check for logged diagnostic codes or active diagnostic codes with the electronic service tool. Refer to Electronic Troubleshooting for more information on the injectors. Also, refer to "Problem 4" .

4. Low Quality Fuel

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

5. Low Fuel Pressure

   Refer to "Problem 4" .

6. Air In Fuel System

   Find the air leak in the fuel system and correct the air leak. If there is air in the fuel system, the air generally enters the fuel system on the suction side of the fuel transfer pump.

7. Worn Valve Guides

   Reconditioning of cylinder head is required.

8. Worn Piston Rings Or Improperly Installed Piston Rings

   Inspect piston rings and install new parts, as required.

9. Worn Pistons

   Check the clearance between the piston rings and the ring grooves in the piston. Ensure that the oil return holes under the oil rings are open.

10. Failure Of Turbocharger Oil Seal

    Check the air inlet manifold for oil and repair the turbocharger, as required.

11. Incorrect Valve Adjustment

    Make an adjustment to the valve clearance. Refer to Testing And Adjusting, "Air Inlet And Exhaust System" .

12. Defective Sensor For The Inlet Manifold Air Temperature

    Check for logged diagnostic codes or active diagnostic codes with the electronic service tool. Refer to Electronic Troubleshooting for more information.

13. Defective Coolant Temperature Sensor

    Check for logged diagnostic codes or active diagnostic codes with the electronic service tool. Refer to Electronic Troubleshooting for more information.

14. Cold Environment

    It is normal to see white smoke for a brief period after starting the engine.

15. Defective Air Inlet Heater

    Check for logged diagnostic codes or active diagnostic codes with the electronic service tool. Refer to Electronic Troubleshooting for more information.

16. Extended Idle Periods

    Do not idle the engine for extended periods of time. This will cause the cylinders to cool. The fuel will not burn completely when the cylinders are operating below normal operating temperatures.

17. Coolant In Combustion System

    Check for a cracked cylinder head.

Problem 21

The Engine Has Low Oil Pressure.

Probable Cause

1. Dirty Oil Filter Or Dirty Oil Cooler

   Check the operation of the bypass valve for the filter. Clean the oil cooler or install a new oil cooler core. Remove dirty oil from the engine. Put clean oil in the engine.

2. Diesel Fuel In Lubrication Oil

   Find the source of the leakage of the diesel fuel into the lubrication oil. Make repairs, as required. Remove the lubrication oil that has been contaminated with diesel fuel. Install new oil filters. Put clean oil in the engine.

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

   Check lubrication in valve compartments. Install new parts, as required.

4. Defective Oil Pump Suction Pipe

   Replacement of oil pump suction pipe is required.

5. Stuck Open Oil Pressure Relief Valve

   Clean the valve and the housing. Install new parts, as required.

6. Defective Oil Pump

   Repair the oil pump or replace the oil pump.

7. Too Much Clearance Between Crankshaft And Crankshaft Bearings

   Inspect the crankshaft bearings and make replacement, as required.

8. Too Much Clearance Between Camshaft And Camshaft Bearings

   Inspect the camshaft and the camshaft bearings. Replace the camshaft and the camshaft bearings, as required.

9. Defective Oil Pressure Gauge

   Install new gauge.

10. Low Engine Oil Supply

    Check the level of the engine oil in order to ensure that it is correct.

11. Defective O-ring

    Check the O-ring in the engine oil line from the engine oil pump to the engine.

Problem 22

The Engine Uses Too Much Lubrication Oil.

Probable Cause

1. Too Much Lubrication Oil In Engine

   Remove the extra oil. Find the source of the extra oil. Put the correct amount of oil in the engine.

2. Oil Leaks

   Find all oil leaks. Make repairs, as required. Check for dirty crankcase breathers.

3. High Oil Temperature

   Check operation of oil cooler and oil temperature regulator. Install new parts, as required. Clean the oil cooler cores.

4. Worn Valve Guides

   Reconditioning of the cylinder head is required.

5. Worn Valve Guide Seals

   Check for leakage around the seals. If necessary, install new parts.

6. Worn Piston Rings And Worn Cylinder Liners

   Inspect piston rings and install new parts, as required. Reconditioning of the cylinder block can be required.

7. Failure Of Turbocharger Oil Seal

   Check the air inlet manifold for oil and repair the turbocharger, as required.

Problem 23

The Engine Coolant Temperature Is High.

Probable Cause

1. Restriction Of Coolant Flow Through Radiator Core Tubes Or Through Heat Exchanger Lines

   Clean the radiator or the heat exchanger and flush the radiator or the heat exchanger.

2. Restriction Of Air Flow Through The Radiator

   Remove all restrictions to air flow.

3. Low Fan Speed

   Check for loose fan drive belts. Adjust fan drive belts to the correct tension. Replace belts, as required.

4. Low Coolant Level

   Add coolant to the cooling system. Check for leaks.

5. Defective Pressure Cap

   Check operation of the pressure cap. Install a new pressure cap, as required.

6. Combustion Gases In Coolant

   Find the source of the leakage of combustion gases into the cooling system. Make repairs, as required.

7. Defective Water Temperature Regulators

   Check water temperature regulators for correct operation. Check the water temperature gauge for correct operation. Install new parts, as required.

8. Defective Water Pump

   Make repairs, as required. Install a new water pump, as required.

9. Too Much Load On The System

   Reduce the load on the system.

10. Incorrect Coolant Mixture

    Ensure that the mixture of water and antifreeze is correct. Refer to the Operation And Maintenance Manual for recommendations on coolant.

11. Defective Coolant Temperature Sensor

    Check for logged diagnostic codes or active diagnostic codes with the electronic service tool. Refer to Electronic Troubleshooting for more information.

12. Air Inlet Restriction

    An air inlet restriction can cause high cylinder temperatures. The higher cylinder temperatures transfer more heat to the cooling system. Refer to Testing And Adjusting, "Air Inlet And Exhaust System" for information on checking the air inlet restriction.

13. Exhaust Restriction

    Restriction in the exhaust system can cause high cylinder temperatures. The higher cylinder temperatures transfer more heat to the cooling system. Refer to Testing And Adjusting, "Air Inlet And Exhaust System" for information on checking for a restriction in the exhaust system.

14. Restricted Air Flow Through The Aftercooler

    Restriction of the air flow through the air to air aftercooler can increase coolant temperatures. Check for debris which would prevent the free flow of air through the aftercooler.

15. Operation At High Altitude

    The cooling capacity of the cooling system decreases when the engine is operated at high altitudes. Ensure that the capacity of the cooling system is adequate for the engine at high altitudes.

Problem 24

The Engine Coolant Temperature Is Low.

Note: For operation in cold temperatures, a full winter front closure or radiator shutters are recommended.

Probable Cause

1. Extended Idle Periods

   When the engine is running with no load, the heat from the engine is removed too quickly.

2. Defective Water Temperature Regulators

   Check water temperature regulators for correct operation. Check the water temperature gauge for correct operation. Install new parts, as required.

3. Very Light Loads

   Very light loads can cause low coolant temperatures because there is less heat in the engine. A slight restriction of the air flow through the radiator will correct this problem.

Problem 25

The Exhaust Temperature Is Too High.

Probable Cause

1. Leakage At Air Inlet System

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

2. Leakage At Exhaust System

   Find the cause of the exhaust leak. Make repairs, as required.

3. Restriction At The Air Inlet System Or The Exhaust System

   Remove the restriction.

4. Defective Turbocharger

   If the wastegate on the turbocharger is not operating properly, excessive boost pressure may be generated. This will result in high cylinder pressure and therefore high exhaust temperatures. Verify that the wastegate is operating properly. Refer to Testing And Adjusting, "Air Inlet And Exhaust System" .

5. Operating Under Heavy Load Below Peak Torque RPM

   The engine should be operated between the rated rpm and the peak torque rpm.

Problem 26

The Starting Motor Does Not Turn.

Probable Cause

1. Low Output Of The Battery

   Check the condition of the battery. Charge the battery or replace the battery, as required.

2. Defective Wires Or Defective Switch

   Replace the wires or replace the switch, as needed.

3. Defective Starter Motor Solenoid

   Install a new solenoid.

4. Defective Starter Motor

   Repair the starter motor or replace the starter motor, as needed.

Problem 27

The Alternator Gives No Charge.

Probable Cause

1. Loose Drive Belt

   Adjust the drive belt to the correct tension.

2. Defective Charging Circuit, Defective Ground Return Circuit Or Defective Battery Connections

   Inspect all cables and inspect all connections. Clean connections. Tighten connections. Replace parts, as needed.

3. Defective Rotor (Field Coil)

   Install a new rotor.

4. Defective Brushes (If Equipped)

   Install new brushes.

Problem 28

The Alternator Charge Rate is Low Or The Alternator Charge Rate Is Not Regular.

Probable Cause

1. Loose Drive Belt

   Adjust the drive belt to the correct tension.

2. Defective Charging Circuit, Defective Ground Return Circuit Or Defective Battery Connections

   Inspect all cables and inspect all connections. Clean connections. Tighten connections. Replace parts, as needed.

3. Defective Alternator Regulator

   Install a new alternator regulator.

4. Defective Rectifier Diodes

   Replace the defective rectifier diode.

5. Defective Rotor (Field Coil)

   Install a new rotor.

Problem 29

The Alternator Charge Rate Is Too High.

Probable Cause

1. Loose Connections On The Alternator Or Loose Connections On The Alternator Regulator

   Tighten all connections.

2. Defective Alternator Regulator

   Install a new alternator regulator.

3. The Field Of The Alternator Is Shorted To Battery Voltage.

   If the field of the alternator becomes shorted to battery voltage, the alternator will charge at the maximum rate. When the battery becomes overcharged, voltage and current can rise to levels that result in damage to the battery. The alternator, the voltage regulator, and any electrical equipment that is being used can also be damaged. The ECM is protected from an overvoltage condition up to 32 volts. DC voltages above that may damage the ECM.

   Correct the short between the field circuit of the alternator and the battery voltage. Repair any electrical equipment that has been damaged. Replace any electrical equipment that has been damaged beyond repair.

Problem 30

The Alternator Has Noise.

Probable Cause

1. Defective Drive Belt

   Install a new drive belt for the alternator.

2. Loose Alternator Drive Pulley

   Check the groove in the pulley that holds the pulley in place. If the groove is worn, install a new pulley. Tighten the pulley nut. Refer to Specifications for the correct torque value.

3. Alternator Drive Belt and Drive Pulley Out Of Alignment

   Align the drive belt with the drive pulley.

4. Worn Alternator Bearings

   Install new bearings in the alternator.

5. Bent Rotor Shaft

   Install a new rotor shaft.

Problem 31

Fuel Is In The Lubrication Oil.

Probable Cause

1. Defective Upper Seal On Unit Injector

   Check for a defective O-ring seal on the top of the unit injector. Remove the fuel supply line at the front of the cylinder head. Plug the return line to the fuel tank. Pressurize the cylinder head. Look for fuel that is leaking between the unit injectors and the cylinder head. If fuel is leaking from an unit injector, remove the unit injector and replace the upper O-ring seal. If necessary, change the oil and the engine oil filter.

   Note: For the proper procedure for the removal and for the installation of unit injectors, refer to Disassembly And Assembly .

2. Porosity In The Cylinder Head

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

3. 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.

4. Defective Seal In The Fuel Transfer Pump

   Check for a defective O-ring seal between the fuel transfer pump and the hydraulic pump. Refer to the Disassembly And Assembly Manual.

Problem 32

Fuel Is In The Coolant.

Probable Cause

1. Defect In Unit Injector Sleeve

   Remove the unit injectors. Inspect the injector sleeves in the injector sleeve bore in the cylinder head. Look for signs of cavitation erosion or signs of cracks. Cavitation on the inside may be due to air bubbles in the fuel. Air bubbles may be due to a leak on the suction side of the fuel transfer pump. Air bubbles may also be caused by combustion gas leakage. Check for cracks at the injector sleeve near the unit injector nozzle. Remove the injector sleeve from the cylinder head. Cavitation erosion on the outside of the injector sleeve could indicate an incorrect coolant conditioner concentration. If any problems are seen, replace the sleeve with a new sleeve. For the proper procedure for the removal and for the installation of unit injectors, refer to Disassembly And Assembly .

Problem 33

The Engine Is Losing Coolant.

Probable Cause

1. Leaks In Hoses Or Connections

   Check all hoses and check all 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

   Pressurize the radiator and the expansion tank with the 9S-8140 Pressurizing Pump and check for leaks.

3. Leaks In The Heater

   Pressurize the cooling system with the 9S-8140 Pressurizing Pump and check for leaks.

4. Leaks In The Water Pump

   Check the water pump for leaks before starting the engine. Start the engine and look for leaks. If there are leaks at the water pump, repair the water pump 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 Manual.

6. Defective Pressure Cap

   Check the sealing surface of the pressure cap for damage. Also check the sealing surface of the radiator for damage. Ensure that the cap is sealing correctly. Check the opening pressure of the pressure cap valve with the 9S-8140 Pressurizing Pump . Also check the sealing ability of the pressure cap valve with the pressurizing pump.

7. Higher Than Normal Coolant Temperature

   As the temperature of the coolant increases, the pressure inside the cooling system increases. When the coolant overheats, the pressure will overcome the sealing ability of the radiator cap. This will cause coolant loss through the overflow tube. Refer to "Problem 23" .

8. Insufficient Expansion Tank Capacity

   The expansion tank can be a part of the radiator or the expansion tank may be a separate unit. The expansion tank capacity must be large enough to contain the coolant as the coolant expands. Ensure that the expansion tank is installed correctly. Ensure that the size meets the recommendations of the OEM.

9. Cylinder Head Gasket Leakage Or Cracks In Cylinder Head Or Cylinder Block

   Remove the radiator cap while the engine is 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 and the cylinder walls for cracks. Check the head gasket surface of the cylinder block for cracks. Install a new head gasket. Tighten the bolts that hold the cylinder head according to the Specifications Section of the Service Manual.

10. Erosion Or Cracks In Unit Injector Sleeves

    If fuel is detected in the coolant, a possible cause is a defective unit injector sleeve. Remove the unit injectors and inspect the sleeves for cavitation erosion or cracks. Replace any defective sleeves. For the proper procedure for the removal and for the installation of unit injectors, refer to Disassembly And Assembly .

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. Cracks In Cylinder Head

    Cracks in the upper surface of the cylinder head can allow coolant to leak into the crankcase. Cracks that are in an area that is between a water passage and an opening into the crankcase can also allow coolant to leak into the crankcase.

13. Cracks In Cylinder Block

    Cracks in the cylinder block that are between a water passage and the crankcase will allow coolant to leak into the crankcase.

Problem 34

Soot Is In The Inlet Manifold.

Probable Cause

1. Engine Design

   A small amount of soot in the inlet manifold is normal for diesel engines. Valve overlap allows the inlet valve to open slightly before the exhaust stroke has been completed. This will allow some soot to be pushed into the inlet manifold.

2. Defective Valve Or Defective Valve Seat

   A defective valve or a defective valve seat allows a large quantity of soot to be pushed into the inlet manifold. Reconditioning of the cylinder head is required.

Problem 35

Air Is In The Fuel.

Probable Cause

Install a 2P-8278 Fuel Flow Tube in the fuel return line. Start the engine and check for air bubbles in the fuel. Air in the fuel system will normally cause the engine to be difficult to start. The engine will usually run rough. The engine will also produce a large amount of white exhaust smoke. Air will generally enter the fuel system on the suction side of 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.

Note: If the engine is equipped with a fuel priming pump, the pump can be used to remove the air from the fuel system. The fuel priming pump is also used to fill the fuel system with fuel from the fuel tank before the engine is started.

If no leaks are found, remove the fuel supply line from the fuel tank and connect the fuel supply line to an outside fuel supply. If this corrects the problem, the suction line (stand pipe) inside the fuel tank has a leak. If this does not correct the problem, check for combustion gas leakage at the base of the fuel injectors. Remove each injector and examine the base of the sleeve and the injector for evidence of nicks or carbon tracking. A magnifying glass and a flashlight may be needed. The lower sealing surfaces of the nozzle and sleeve should be smooth. If any defects are noted, the sleeve can be reamed in order to restore the surface. Refer to Special Instruction, SEHS9120, "Using the 127-3458 Sleeve Replacement Tool". Check the O-ring on the injector tip and check the upper seal O-ring. Replace O-rings, if necessary. For the proper procedure for the removal and for the installation of unit injectors, refer to Disassembly And Assembly .

The temperature of an exhaust manifold port can be an indication of a cylinder that is receiving fuel that contains air. Check the exhaust manifold temperatures and compare the results. An exhaust manifold temperature that is lower than normal indicates that the cylinder may be receiving air from the unit injector. The color of the exhaust smoke can indicate that a cylinder has a combustion leak. The engine will produce smoke that is gray or white in color.