When you have problems with your vehicle's exhaust system, it is typically easy to spot based on the smoke coming out of the exhaust. The type of smoke, particularly the color, can tell you a lot about the problem actually is. Here are some common colors of smoke that come out of the exhaust and what each of them might mean.
The first color smoke you might see come out of your exhaust is white. White smoke can be a minor or severe problem, so you should pay attention to the thickness of it. If it looks sparse and like a thin vapor, then it is likely due to a buildup of condensation in the exhaust. This is common when it is cold outside and you have just started your car; little bits of smoke come out when it is warming up.
On the other hand, when the smoke billows and becomes a large cloud that you can see clearly outside your back window, it could be a more dangerous situation. This may be from a damaged cylinder head or a blown head gasket. Make sure you bring your car in for service if you see this type of white smoke.
There are a few different things that can cause gray smoke to come out of your exhaust. Oil problems are common, such as having an oil leak or burning oil. It may also be from automatic transmission fluid that is burning in the engine or from a damaged turbocharger. Since it can be so many different things, it is best to let your mechanic know you have been seeing gray smoke. They will be able to diagnose the problem more thoroughly.
Blue smoke is most often caused by burning oil. Oil burns in your engine when the valve guide seals are worn or the piston rings need to be replaced. When there is wear on these parts, it causes the oil to leak and stop lubricating the parts. This can lead to burning oil. Therefore, if you see blue smoke, look for signs of an oil leak. You might see oil underneath your car when you park it, or the dip stick will say the oil level is low even though you know you filled it recently.
Black smoke is usually caused by your engine, such as if it is burning through the fuel too quickly. When you have this color, check the air filter, fuel injectors, and fuel pressure regulator. Also check to see if there is a blockage in the fuel return line.
Of course, if you see any of these unusual smoke colors coming from your vehicle, it is always helpful to contact an auto repair mechanic. You can find one at this website or others like it: http://www.coveysauto.com.