White Smoke At Startup


My car is a 2001 Toyota Camry LE with 35,000 miles on it. When I start it while the engine is cold it emits a quick puff of white smoke. I’ve read so many theories about the cause of this that it makes my head spin! I guess it boils down to a leaking of the valve stem seals, but there’s no evidence of that - yet. Is there a way to tell?


It’s normal for water vapor to be emitted from the exhaust system when the engine is first started. As long as the engine coolant level never drops, it’s nothing to worry about.



If it put out white smoke continuously, that would be coolant getting into a cylinder and it would be something to worry about. As Tester pointed out, all engines produce water vapor as part of combustion of hydrocarbons, and a cold engine (just started) isn’t hot enough to keep the vapor from condensing into fog by the time it gets to the tailpipe. Just check the coolant level once in a while if you’re worried. I don’t know why you’re mentioning valve stem seals… that would leak oil into the intake and cylinders, and produce blue smoke.