White thick smoke coming from exhaust on startup does die down after 30 sec or so then as soon as you rev or drive off its a constant white thick cloud. Don't lose any coolant .It's a 2000 Mitsubishi Legnum non turbo any help will be grateful

  • If the smoke lingers a long time, then it is oil smoke, if it dissipates at a moderate speed, then is is steam from a coolant leak into one or more of the combustion chambers,
    – Moab
    Commented Apr 7, 2018 at 15:59

2 Answers 2


Sorry for the late response, but this can actually be a few things. As another user mentioned, it is potentially the head gasket but DO NOT tear things apart until you test. Parts shops rent out a kit to test your coolant for combustion gases. If you have a blown head gasket, this test will prove positive almost every time.

A few other signs of a bad head gasket: Overheating after ~30 min of driving Chocolate milk colored oil crusty deposits under the radiator cap.

Another possibility would be the compression rings in the engine, enough of a gap in a bad oil scraper, the oil WILL get into the combustion chamber, causing you to burn oil directly from the crankcase. this happens when your piston rings, become seated incorrectly, causing them to leak. Less commonly, but sometimes the case, oil can leak from your heads through the valve seals. this can cause a rather large amount of oil to enter the chamber through your intake valves. Some symptoms of something like this include:

  • Combustion blow-by (check for smoke/particle emissions from oil fill hole)
  • Poor Performance

Good luck!


Sounds like you have a blown head gasket. You'll either need to get it replaced or get a different engine for your vehicle.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .