Color-Coding Your Vehicle's Exhaust Smoke


A healthy, running car engine should not billow any smoke. If you start seeing exhaust smoke coming from your vehicle, it can cause concern. Thankfully, you can usually identify the problem by analyzing its colors. Blue, black/grey, and white exhaustsmoketypically indicate a leak, causing fluid to burn with your fuel and air mixture. Below are what the colors mean:

Blue Exhaust Smoke

If you see blue exhaust smoke from the tailpipe, it is most likely a consequence of the engine burning motor oil. Blue exhaust smoke typically occurs due to one of the following problems:

  • Motor oil leaking in the combustion chamber
  • Deteriorated piston rings
  • Old valves and cylinders

Black or Gray Exhaust Smoke

If your exhaust smoke is black or dark gray, it means that the air and fuel mixture that is being burned is too rich. In some cases, it may also mean that the engine is burning oil as well. Here are some common explanations for black/grey exhaust smoke:

  • Leaking oil
  • Faulty fuel injectors or other fuel system failure
  • Clogged air filter

White Exhaust Smoke

Before you start stressing about seeing white exhaust smoke, please make sure it is not steam or water vapor. Steam is a harmless problem if it happens upon engine startup and goes away after several minutes. However, thick white clouds of smoke could indicate the following issues:

  • Cold engine
  • Leaky head gasket
  • Cracked blocked or cylinder head

If your motor vehicle has colorful exhaust smoke coming from the tailpipe, we invite you to our auto repair shop for an inspection. The team at Hoesly Automotive will get you the suitable repairs so that you can be back on the road safely.

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