Note: Some white smoke may be present during cold start-up conditions when the engine is operating normally.
Probable Causes
- Cold ambient air temperature
- Low jacket water coolant temperature
- Extended idle periods
- Low quality fuel
- Cylinder head gasket
- Inoperative air inlet heater (if equipped)
- Incorrect valve adjustment
- Incorrect fuel injection timing
- Misfiring cylinder
- Low cylinder compression
- Faulty unit injector
Recommended Repairs
Cold Ambient Air Temperature
When the ambient air temperature is cold, the cylinder temperature is cooler. Not all the fuel will burn in the cylinders. The fuel that does not burn comes out of the exhaust as white smoke. White smoke is normal in cold temperatures until the engine has reached normal operating temperatures. There will be less white smoke if No. 1 diesel fuel is used.
Low Jacket Water Coolant Temperature
If the jacket water coolant temperature is low the engine will produce white smoke. Ensure that the normal operating temperature for the engine is reached.
Extended Idle Periods
When an engine runs at idle speed for a long period of time, the cylinders cool and all of the fuel does not burn. Do not idle an engine for a long period of time. If long idle periods are necessary, use No. 1 diesel fuel.
Low Quality Fuel
Check the API of the fuel. Refer to Troubleshooting, "Fuel Quality".
Cylinder Head Gasket Leak
Remove the radiator cap. Start the engine and 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 following areas for cracks:
- Cylinder head
- Cylinder walls
- Gasket surface of the cylinder block
Use a new head gasket when the cylinder head is installed. Refer to the Specifications module for the proper bolt tightening sequence.
Inoperative Air Inlet Heater
Check the air inlet heater for proper operation. Refer to Troubleshooting, "Inlet Air Heater".
Incorrect Valve Setting
Check the valve adjustment and make necessary adjustments. Refer to the Systems Operation, Testing And Adjusting module.
Incorrect Fuel Injection Timing
Check the fuel injection timing and make necessary adjustments. Refer to the Systems Operation, Testing And Adjusting module.
Misfiring Cylinder
If the engine is misfiring, refer to Troubleshooting, "Engine Misfires, Run Rough Or Is Unstable".
Low Cylinder Compression
Inlet/exhaust valves or piston rings are leaking compression. Disassemble the engine and find the source of the leaks.
Faulty Unit Injector
Faulty unit injectors will normally cause the engine to misfire which will cause the engine to run rough. Faulty unit injectors can also cause too much smoke even if the engine is running smoothly. Remove the unit injectors and check the unit injectors. Use the 1U-6661 Pop Tester Group to check the unit injectors for proper operation. Refer to Special Instruction, SEHS9787. Use the go/no-go gauge to test the unit injector height. Check the injectors for external leakage.