I'm a new member and recently had my head gasket replaced 2 months ago on my 94 vortec blazer. Also had the oil and trans cooler lines replaced 2 weeks ago. Suddenly, after I let the Blazer sit for 24 hrs...it smoked white from the exhaust but then stopped. It will NOT smoke unless it sits for over a day or more. The mechanic wants me to leave there for a couple days to determine problem. I wonder if they did something to the exhaust manifold when they spent 6 hrs replacing the oil/trans cooler lines....but it sure seems like a coincidence that the smoke started ONLY after the lines were replaced. It does not smoke when I accelerate. Any suggestions?

 

Is it smoke, or steam? Its normal for cars to have some steam coming out of the exhaust in the morning, or after sitting overnight. Its just moisture (condensation) in the exhaust system being evaporated by the hot exhaust gases. The steam doesn't usually last long, gone in the first ten minutes or so of driving.

If its not that, check your coolant. White smoke usually means a head gasket leak, and the engine is burning antifreeze/water.

 

Thanks for responding about my issue. I am pretty sure its smoke when I first start up after a day or so of being parked. It lasts/clears within 10 seconds...but it is a respectable cloud...picture me in the driver's seat with the door open...so, with the exhaust pipe on the opposite rear side of the vehicle and when I start it up..within seconds I'm seing the cloud coming over the roof and into the car...a noticeable amount of smoke...but within 10 seconds its over. Exhaust pipe has no moisture dripping. The mechanic said he needs to keep it for a couple days to determine cause. Still, very strange that it NEVER smoked before...not before or after I paid $400 for the head gasket. It was only just after they replaced the oil and trans cooler lines did it start smoking. Antifreeze up to level, oil is level, inside oil cap is clear not milky. Mechanic looked for any moisture or leaks....none...! Afterall, he spent over 6 hrs replacing those cooler lines...thats a big teardown...and he sees no leaks. My guess....exhaust manifold?...valve guides?...pvc? ....I'll leave it parked for a couple days and see if it explodes again. Then its off to the service guys who are costing me more than this truck is worth.

 

+1, classic sign of LIM gasket failure as well. Does the exhaust smell like coolant? Does the oil filler cap smell like coolant? Pull the dip stick, does the oil on it look milky? Is it over heating?

If you answered yes to any of those questions...you have a bad LIM or head gasket.

 

I had the intake manifold gasket repaired/replaced 2 months ago. No milky dipstick. No loss of coolant. The smell of the white cloud is mild and hard to describe. Engine never overheats , oil filler cap is normal, and truck has new antifreeze coolant when they changed the manifold gasket. Oil changed and new oil/air filters. The problem started immediately after they changed the oil and trans cooler lines. Truck has 107,000 miles and never smoked until 2 weeks ago when they did the oil/trans lines. So the answer to your question /50 lbs cat (do you really have a 50 lbs cat?)...is "Nope!"

If its the valve seals that are bad... what is the cost to repair/replace the seals? Would the smoke get worse and would it hurt anything if I decided not to repair it?

I assume the white smoke from my exhaust is probably the leaking valve guides on my 94 V-6 blazer. If it is, what is the average cost to repair so I can act knowledgeable at the service station. If not fixed...will the white smoke get worse? Very embarassing to the neighbors.

 

Well, since it started after the line replacement it makes me think the two are connected. I can't think of what it might be however.

White smoke it coolant or steam. Blue smoke is oil and black is fuel. So I don't think its a valve issue. And to answere your question, no my cat isn't actually 50 lbs lol but he is very fat lol

 

It might be a good suggestion to restrict the kitty from eating too much. Not healthy for them. Did you know that cats can get diabetes from being overweight?

 

As previously mentioned, white smoke is water. It sounds like you have a slow leak in the head gasket. When it sits, water leaks into the cylinder. It's possible that under pressure it seals, hence no smoke when running. Either that, or it's a small enough leak that it doesn't show when running. Your coolant remains pressurized after shutdown, so it could be building up in the cylinder while it sits. As mentioned, could be the LIM gasket as well.

Pull your spark plugs. My guess is that one of them will show signs of water burning. Google up a chart showing spark plugs and various malfunctions for pictures. That'll get you started towards figuring this out.

It's possible that the head was warped by improperly torquing it down when the head gaskets were changed. If you pull the head to replace the gasket have that checked out first before you re-install the head. If warped it'll either need to be machined or replaced, depending on the severity of the warp. If you surface the one head, you really need to do them both. If you're lucky, it's just a bad gasket. What brand gasket was it? I'm a big believer in Fel-Pro gaskets.

Good luck!

BTW, you mentioned a service station? Umm, the odds of a mechanic at a service station knowing what he is doing are somewhat slim. I'm sure there are some good ones out there, but there are an awful lot of bad ones.

Unfortunately, my experience with Chevrolet service departments has been really bad as well. I'm not saying they're all bad, but every dealership service department I've ever dealt with has been horrible. (Chevy and Honda both.) Some were just bad, others had good mechanics but very dishonest management. My wife's Honda started stalling when I was out of town for a few weeks. She took it in to the dealership where they found $2500 worth of things wrong with the car. None of them had anything to do with the engine stalling. I told her to live with it till I got home. I fixed the stalling in about an hour, the fuel pump relay was going out. Not one thing on the dealerships $2500 list was actually bad. Not one thing. They lied about everything. They had actually pressured my wife, telling her it would be illegal for her to drive her car with everything it had wrong with it. F&^%ing liars and thieves.

Finding a good, honest mechanic can be hard. Read online reviews and check with local forum members--not just this forum, but any around--and try and find a shop with lots of great feedback. When you find a good mechanic post up reviews so that he and others can benefit.

 

Thanks for your ideas...I figure I should take it to the same mechanic who did the manifold and cooler lines....since he's torn it down twice and should know the cause. I 'll let you guys know the answer later this week.

 

Late info...after over 2 days of letting the Blazer sit...I gathered a friend to watch for the smoke cloud from the exhaust when I started it up. No smoke at all!! No moisture drip...BUt, I still just drove it to the mechanic to check. I hope its not a head gasket! I am seriously considering a gasket sealer if, in fact, they claim its the head gasket. The truck is not worth the expensive fix! Time will tell!