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smoke coming from the tailpipe is not good news, but does not necessarily mean the engine needs rebuilding. First, you need to determine what color of smoke is coming from the tailpipe. The three most common colors of smoke that can be emitted from the engine and billow from the tailpipe are as follows:
1- White smoke: White 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. There are special gaskets (head gaskets are the primary gaskets) that keep the antifreeze from entering the cylinder area. The cylinder is where the fuel and air mixture are being compressed and burned. Any amount of antifreeze that enters this area will produce a white steam that will be present at the tailpipe area.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. You can look at the engine oil dipstick, or look at the underside of the engine oil filler cap. If the oil is contaminated with antifreeze, it will have the appearance of a chocolate milkshake. Do not start the engine if the oil is contaminated with antifreeze as serious internal engine damage can result.
How did antifreeze get in the oil or cylinder in the first place? The engine probably overheated and a head gasket failed due to excessive heat, thus allowing antifreeze to enter the cylinder (where it is not meant to be).
2- Blue smoke: Blue 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 high mileage vehicles than newer cars with fewer miles.
3- Black smoke: Black 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. Black smoke out the tailpipe is the least cause for alarm. Excess fuel will usually effect engine performance, reduce fuel economy, and produce a fuel odor.
when the engine is due for service and when the oil in the engine is due for change
