What color of smoke indicates that oil is being burned in the combustion chamber?

The presence of blue smoke from the exhaust indicates that oil is being burned within the combustion chamber of an engine. This occurs when oil seeps into the combustion area, which can happen due to worn piston rings, valve seals, or other internal engine issues that compromise the seals and allow oil to mix with fuel during combustion.

Blue smoke is typically indicative of a problem that needs to be addressed, as burning oil can lead to increased emissions, loss of engine performance, and potential long-term damage to the engine components. Recognizing blue smoke allows technicians to investigate and diagnose oil-related issues promptly, ensuring the engine operates efficiently and reduces harmful emissions.

In contrast, white smoke often suggests water or coolant is entering the combustion chamber, while black smoke indicates an overly rich fuel mixture. Gray smoke can be more ambiguous, but it frequently ties to incomplete combustion or a combination of fuel and oil issues. Understanding these differences is crucial for proper engine diagnosis and repair.