Cummins ISX & ISB Excessive White Smoke


Several things could be causing white smoke in your Cummins Semi:

Cause: Stiction in the injectors

Solution: Use one full dose of Stiction Eliminator to clean out your injectors.

Cause: Poor fuel quality

Solution: If you suspect poor fuel or water in fuel, treat with Diesel Extreme and change the fuel filter.

Cause: Blown head gasket

Solution: If the truck is using excessive coolant or is smoking white all of the time, check the head gasket.


White smoke is caused by either unburned fuel or coolant. On the common rail Cummins, white smoke is more characteristic of an injector problem.

If the exhaust smells almost like bug spray, it is unburned fuel. Injector and poor fuel problems can typically be cleared up by treating the truck with Diesel Extreme.

If the exhaust smells slightly sweet, it is coolant. This can be associated with a head gasket failure. This can also cause a mix of coolant and oil.

If it is smoking white all of the time and the exhaust smells almost like bug spray, feel free to contact one of our diesel experts.


Excessive White Smoke - Heavy-Duty Cummins Symptoms
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