Mitsubishi: Smoke, blown head gasket, valve seals


Question
I have 1997 Eclipse automatic.  When I start the car after it has sat overnight or a while, a puff of white smoke comes out of the exhaust.  After running for about 15 seconds there is no more smoke.  What is this and how much will it cost to fix.  Thanks in advance!
Brad

Answer
Brad,

The most likely suspect is that the valve seals are dripping and overnight a little has dropped down into the combustion chamber. When you start the engine, it burns up in seconds and is gone. A blown head gasket will cause the same symptom but it usually gets worse as things heat up. A clue to a bad head gasket comes with milky oil on the dip stick.

Bill Kenner
Nashville, TN