White Smoke-Very dense, white smoke present in vehicle exhaust gases is symptomatic of transmission fluid being sucked into the engine's combustion chamber and burned. This white smoke is not normal and, if present in the exhaust, generally indicates a problem with the transmission modulator valve. This problem can typically be corrected by replacing the modulator valve.

Black Smoke-Black smoke is the result of partially-burned gasoline being carried down the exhaust. This unburned fuel is wasteful, expensive, and a carcinogen. Black smoke can usually be eliminated with carburetor or fuel injector repairs.

Blue Smoke- Pale, bluish-white smoke is the result of engine lubricating oil being burned in the engine's combustion chamber. The most common causes of blue smoke in the exhaust are worn piston rings or loose valve guides. Both conditions involve major engine repairs to correct. You can often diagnose the source of this blue smoke by performing an engine wet/dry compression test.