My 96 Deville is releasing a puff of smoke or steam every 2-3 miles on the highway. Also losing antifreeze but I'm not sure it is related. Running great, it's the weirdest thing I've ever seen.......Any ideas?
Thanks, Randy

 

Sounds like the classic head gasket gone bad. Go to a reputable shop and have either a compression or a leak down test done. The leak down test is more accurate as the compression requires a fully charged battery to keep cranking the engine over while the leak down test uses a compressor to maintain air pressure.

 

I'll assume the smoke is white? If the loss of coolant is related, check heads........................soon.

jst post was 53 seconds before mine and he is absolutely correct.

 

Unfortunately the classic head gasket failure symptoms. You will eventually do serious damage to your engine by continuing to drive the car in this condition.

 

I've never seen a head gasket that releases a cloud of smoke and then stops for a couple miles, then does it again. Since my original post I replaced the PCV valve and drove it home 25 miles without incident.

 

My post advised that IF the loss of coolant was related I would check the heads. Since it appears tha it is not related, do a pressure check of cooling system to determine the cause of loss of anti freeze.

Good luck.

G.A.R.Y.

 

Is the smoke/steam visable when driving or just when you stop?

 

So far it's been on the highway. When I replaced the water pump 4 mos ago I also replaced the rad cap. I'm gonna have the cap tested today. I'm wondering if pressure is building up and when the cap can't hold it the released antifreeze is hitting the exhaust and in 20deg weather its creating a vapor cloud that looks like smoke for a second.

 

I'd also suggest checking the water pump repair for leaks around the gasket. The water pump is in a location that can leak onto hot engine parts as well and create a steam like cloud too. Do you know if all the coolant was changed for the pump repair? Was sealer put in?

 

The part that puzzles me is the clouds are in BIG BURSTS and then nothing for a few miles. Yes, I put the sealant pellets back into the system (twice). I did the water pump about 3 mos ago, the coolant just started leaking about 2wks ago. It's a mind bender. By the way the DIC is showing a steady 208-218deg on the highway so I don't think the thermostat is sticking as a friend suggested.

Thanks for the input, Randy