White smoke coming out of the exhaust


What do you think is the problem if the exhaust is spewing thick white smoke?

It is a Nissan 90 Altima, 149k mileage. It passed smog last renewal 1st quarter this year.

I would appreciate your detailed explanation.

Thank you very much.



This is a wild guess, but could it not be a blown head and antifreeze is getting burned? I believe antifreeze burns with a white vapor. See my comment on another thread about looking at antifreeze in radiator with cap off (cold!!!) and start engine to see foam/bubbles if head is blown.


Thick white “smoke” is actually steam. Water (engine coolant) is getting into the combustion chambers and being vaporized. The most likely cause is a blown head gasket.


Does the smoke smell like gasoline? If so it’s probably not steam, but uncombusted fuel. This could be a computer or sensor related problem and not a head issue.


Excess unburned fuel would not cause thick white smoke, but black smoke. White like this is undoubtedly a blown head gasket.

It’s an expensive repair, and one that I’d think over before having done to a 17 year old car.


Spewing thick white smoke? This is almost certainly a blown head gasket. Check your coolant level and condition of your engine oil and then report back. Rocketman


if you spend the money, just get a rebuilt engine or one imported from Japan (look up nippon motors). Cost is pretty similar and you get an engine with 30,000 miles on it instead of 170,000.