1. Autos
Send to a Friend via Email

Your suggestion is on its way!

An email with a link to:

http://autorepair.about.com/od/troubleshooting/a/TS_exhaust_2.htm

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.

Gray or Blue Smoke

Gray or Blue Smoke Coming From Your Exhaust Pipe

By

Symptom: Gray or blue smoke from the exhaust. You notice gray smoke coming from the exhaust when you start your car. The smoke may or may not disappear after the car is warmed. If it is, it is less noticeable. The smoke may have a bluish tint to it.

Possible causes:

  1. The engine's piston rings may be worn.
    The Fix: Replace piston rings. (Generally not a DIY job)
  2. The engine's valve seals may be worn.
    The Fix: Replace valve seals. (Generally not a DIY job)
  3. Damaged or worn valve guides.
    The Fix: Replace valve guides. (Not a DIY job)

Symptom: Engine uses more oil than normal, and there is some smoke from the exhaust. The oil level is low between oil changes. It appears that the oil is being burned by the engine because of the smoke in the exhaust. You may or may not notice the engine doesn't have the same power as it used to.

Possible causes:

  1. The PCV system is not working properly.
    The Fix: Replace PCV valve.
  2. The engine may have mechanical problems.
    The Fix: Check compression to determine engine condition.
  3. The engine's piston rings may be worn.
    The Fix: Replace piston rings. (Generally not a DIY job)
  4. The engine's valve seals may be worn.
    The Fix: Replace valve seals. (Generally not a DIY job)
  1. About.com
  2. Autos
  3. Auto Repair
  4. Troubleshooting
  5. Blue Gray Exhaust Smoke Troubleshooting

©2014 About.com. All rights reserved.