What could it be when it throws white smoke through the tail pipes

MMALDO

MEMBER
1997 CADILLAC DEVILLE
100,000 MILES

I had a water leak 2 days ago where the water pump is loctated. I removed the whole base where the water pump is, I found out it was the 4 gaskets that bolt to the block I repaired it and put it back together, so when I put water in it I started up car and left the car running for about 15 mintues after the 15 minutes I saw the car trying to stall so I checked the gauge and saw that the car was over heating I saw white smoke coming from the tail pipes, first thing that came to my mind that it was the head gaskets so I checked the oil for any signs of water in the oil.I just bought the thermostat and will installed it, so I installed it and waited 25 minutes fans come on so I think that solve my problem but what would cause white smoke coming out of my tail pipes when it was over heating

1 Reply

CARADIODOC

MECHANIC
33,925 POSTS

White smoke is a sign of burning coolant from a leaking head gasket. If there was an air pocket that wasn't bled out of the cooling system, that would prevent the thermostat from opening leading to overheating. Thermostats open in response to hot liquid, not hot air. While that air pocket could lead to overheating, it's kind of a stretch to say that caused the leaking head gasket.

https://www.2carpros.com/articles/head-gasket-blown-test

While it didn't help the situation, that leak was most likely about to occur on its own soon.