1. Autos
Send to a Friend via Email

Your suggestion is on its way!

An email with a link to:


was emailed to:

Thanks for sharing About.com with others!

You can opt-out at any time. Please refer to our privacy policy for contact information.

What Does This Exhaust Color Mean?

Blue, White, Gray or Black Smoke in Exhaust


Just like you can examine an animal's poo to get an idea of its health, you can pay attention to the quality of your car's exhaust to get an idea of what's going on inside the engine. As the engine burns fuel and creates exhaust, lots of different things are happening. Unfortunately some of these things aren't supposed to happen. Things like burning oil, evaporating coolant and leaving unburned fuel in the exhaust -- these are not good to see. Pay attention to what's coming out and you can get a good idea as to what problems your engine may be having, often before they get bad. This saves you money.

We've listed the most common symptoms and their causes to help you troubleshoot your exhaust by color and by smell. Follow the links to read up on what's happening in your engine.

Blue or Gray Smoke

White Smoke or Water Vapor

Black Smoke

Fuel Odor or Drop in MPG

  1. About.com
  2. Autos
  3. Auto Repair
  4. Troubleshooting
  5. My Exhaust Smoking Color, What's Wrong

©2014 About.com. All rights reserved.