In a heavy vehicle, what is usually the main reason for the exhaust pipe emitting white-blueish smoke?

Question

DentroTest · Accepted Answer

Continuous emission of white-blueish smoke from the exhaust pipe is the characteristic symptom that the engine is burning lubricating oil. This happens when the lubricant seeps into the combustion chambers, usually through worn piston rings, clearance in the valve guides or gaskets in poor condition, resulting in oil consumption far above normal. By contrast, a dirty air filter or worn injectors supplying excess fuel produce incomplete combustion with a lack of oxygen, which generates black smoke. If the smoke emitted were dense, persistent white (water vapor), it would indicate coolant entering the cylinders.

In a heavy vehicle, what is usually the main reason for the exhaust pipe emitting white-blueish smoke?

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