Do you know when to worry if your car is smoking?

January 04, 2009

Thanks to trustmymechanic.com, we know that smoke coming from the tailpipe is not necessarily good news, but it does not mean the engine needs rebuilding, either. Here are the three most common types of exhaust smoke, with tips about what could be causing it, and suggestions on how to deal with it.

White Smoke
White exhaust smoke is caused by water and or antifreeze entering the cylinder, and the engine trying to burn it with the fuel. The white smoke is steam. If white smoke is present, check to see if the proper amount of antifreeze is inside the radiator and the overflow bottle. Also check to see if antifreeze has contaminated the engine oil.

Blue Smoke
Blue exhaust smoke is caused by engine oil entering the cylinder area and being burned along with the fuel air mixture. As with the white smoke, just a small drop of oil leaking into the cylinder can produce blue smoke out the tailpipe. Blue smoke is more likely in older or higher-mileage vehicles than newer cars with fewer miles. Using thicker weight engine oil or an oil additive designed to reduce oil leaks might help reduce the amount of oil leaking into the cylinder.

Black Smoke
Black exhaust smoke is caused by excess fuel that has entered the cylinder area and cannot be burned completely. Another term for excess fuel is “running rich.” Poor fuel mileage is also a common complaint when black smoke comes out of the tailpipe. Excess fuel will usually effect engine performance, reduce fuel economy, and produce a fuel odor. Do not start the engine if a heavy, raw fuel smell can be detected in the engine oil. Call your mechanic and advise him of what you have found.

There's one more form of smoke to avoid at all costs: Tobacco smoke. Smoking in cars while children are present is illegal in several states.

By Brandy Schaffels
AskPatty.com Editor