Is it a blown head gasket?

STSGIRL96

MEMBER
CADILLAC STS

I just recently purchased a 1996 cadillac STS. It has a 164,xxx miles. It has the 4.6 liter V8 engine. The information center reads "service emissions. The service engine light is constantly on. I have to keep refilling coolant and oil. The temp gage...which I watch constantly gets warm when I drive it more than 15 min. When I first start it...white smoke appears then is gone. It is now starting to idle a little rough. Is it a blown head gasket or something way more serious? I love this car. Hope to have it for a while. Thanks! Barbie

1 Reply

SERVICE WRITER

MECHANIC
9,123 POSTS

AT this point it may just be a headgasket, overheating can cause a head to crack however. Since your losing both coolant and oil, you are possibly burning it at this point. I have seen intake manifold gaskets be a problem on other gm engines, but I assume this is the northstar engine?

With it getting a rough idle, the plug may be fouling or excessive coolant is now getting into the cylinder. Don't put this off any longer, get it into a shop and have them properly diagnose it. IF too much coolant gets into the compression chamber it can turn it into scrap metal. However the northstar engine typically allows gases into the coolant super heating it and overheating the motor. Headgaskets are common on the northstar and also have a problem with the headbolts snapping when removing them.