Caddilac deville2004 oerheati g and heat not working g
If you have the Northstar V8 it's going to be the head gaskets. They all blow head gaskets. Check for combustion gasses in the coolant. You can get a chemical additive for this or your mechanic can do the test. To replace the head gaskets correctly you're looking at upwards of $3500. For starters the engine and transmission have to both be removed from the bottom of the car. It's not possible to do the job any other way. In my opinion it's not worth fixing. HTH. -Jim
Djd you onstall the thermostat in the correct position.. If not it could cause the problem your having.
Search Cadillac DeVille Questions
Are you a UK consumer? CarGurus now has a discussion forum in the UK.
Cadillac DeVille Experts