1. White Smoke or Water Vapor
White smoke may come from the muffler when you start your car if it is cold out. However, if it doesn’t disappear after the car is warmed, it could be caused by a crack in the coolant pipe that’s causing coolant to leak into the combustion chamber. Or, there may be a crack in the cylinder head or the exhaust port facility. This is a serious problem and usually requires extensive work.
2. Blue or Gray Smoke
Gray smoke may come from the muffler when you start your car. The smoke may or may not disappear after the car is warmed, but it is just less noticeable. Though usually not as serious as white, grey smoke usually indicates that oil has gotten into the combustion chamber or on the cylinder head, indicating a leak. This is usually easy to find, but can be expensive to fix. The best case scenario, however, is that your vehicle needs an oil change.
3. Black Smoke
Black smoke may come from the muffler when you start your car and it may or may not disappear after the car is warmed. You may notice the engine running rough or misfiring. Black smoke often signifies the most serious problems and may indicate that your engine is burning oil. Sometimes this means you have a blocked air filter, or your injection system is malfunctioning.
If your muffler is showing any of the tell-tale signs above of exhaust system problems, it would be wise to have it checked out by a certified auto mechanic as soon as possible. A little prevention now can save a more costly repair down the road.