What Your Car’s Exhaust Smoke Can Tell You


Driving and colors go hand in hand. Traffic lights and signs are often color-coded for easy understanding, leaking fluid from your vehicle can alert you to certain systems that need attention, and your exhaust system swaps shades for much the same reason. Here are a few tips to help you decode exhaust smoke and learn if your engine needs a tune-up, something has sprung a leak, or something more serious is at play.

Blueish or Grayish Smoke

If you see either of these shades, be warned–something is off. In most cases, these colors indicate an oil leak, either from a worn valve seal, damaged cylinder or failing piston ring. Note: Blue smoke accumulating during acceleration points to piston ring damage, but if it occurs when you let off the gas, it's more likely a cylinder head valve. In either case, you should take your car into a mechanic as soon as possible.

Thin White Smoke

If smoke is light-colored and thin, you probably have nothing to worry about, as this is most likely water vapor that has collected in the exhaust system (a natural occurrence on cold days).

Milky White Smoke

A bad sign, steady streams of thick white smoke coming out of the tailpipe could indicate a leaking head gasket. If this happens, coolant could end up in the combustion chamber where it will heat up and get blown out the exhaust when the engine ignites. More importantly, a coolant leak in hot weather can quickly cause your engine to overheat, leaving you stranded on the side of the road with smoke coming out of more places than one. If it's not a leak, you might have a cracked cylinder head. In either case, serious repairs are in your future, so having things checked out right away will minimize residual fallout.

Black Smoke

Another sign your car is in distress, black smoke generally means it's burning too much fuel. Unfortunately, several factors can cause excess fuel consumption, including a damaged fuel injection system, clogged air filter, a blocked manifold, or something more serious.

Bottom Line

Keeping an eye on your exhaust system can help you detect problems with your vehicle early on. If you notice any of these unusual colors, have your vehicle inspected as soon as possible.

To make sure your San Jose car stays healthy and the earth happy, call Dhillon Motorsports, formerly known as Smog Man San Jose today and schedule an appointment with our team of experts.

Call Dhillon Motorsports, formerly known as Smog Man San Jose for an appointment today!