Colors of Exhaust Fumes

The color of the exhaust from a vehicle can give us an idea about what's happening inside the engine. Vehicle owners should pay special attention if the exhaust is colored. It indicates any possible default in your engine such as unburned fuel, burning of engine oil, damaged valve and piston parts, etc.

Blue/ Gray smoke:

Blue smoke is a clear indication of burning of engine oil or other lubricants during combustion. The valve seats when damaged can allow few amount of lubricant oil to leak through it and that oil mixes with the air-fuel charge and later when it is burned, produces blue colored smoke. It may also occur in cases where the piston rings are worn out and engine oil seeps through it from crankcase. The engine oil burns with the fuel and produces blue smoke. One should regularly check the engine oil levels. If the parts are worn out, it should be replaced with new ones to avoid ant further issues. Excess oil levels can also cause this problem, hence oil level should be maintained properly.

White smoke:

White smoke is a result of the coolant being burned during combustion. Cracked cylinder head, blown head gasket and cracked cylinder blocks can help the coolant to seep through and burn during combustion. White smoke can also be caused by condensation when the engine is too cold or when water gets vaporized during combustion.

Black smoke:

Burning too much fuel can result in black smoke. Less amount of air can lead to incomplete fuel combustion. Clogged air filter, carburetor malfunction, fuel injector malfunction, improper ignition timing are some of the causes for incomplete fuel combustion