Smoke Cloud
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Joined: Apr 2004
Posts: 62
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From: Fayetteville NC
Smoke Cloud
Any ideas on the cause of a cloud of smoke blowing out the exhaust when I start it? It seems to happen more when the car has been driven recently...like when I stop at the gas station, or park for 5-10 minutes and then start it again.
Instructor
Joined: Sep 2002
Posts: 210
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From: Southfield Michigan
Re: Smoke Cloud (jvet)
Sounds like valve seals to me too. Except mine does not do it if it was recently run. Only in the morning and what not. Also changing the oil helps keep the smoke under control :D At least fixing valve seals is not too awful of a job. :seeya
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Joined: Apr 2004
Posts: 62
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From: Fayetteville NC
Re: Smoke Cloud (BookSmart)
I haven't done anything more than typical maintenance previously. How long should I allow for this job, and what is a good how-to manual I can refer to?
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Team Owner
Joined: Dec 2000
Posts: 21,094
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From: Phila., PA burbs
Re: Smoke Cloud (my1st_vette84)
Would the the Corvette shop manual be my best how to reference for the valve seals?
Race Director
Joined: Sep 2000
Posts: 17,298
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From: The Top of Utah
Re: Smoke Cloud (my1st_vette84)
The smoke from oil should be blue. Black is excess fuel and white is steam from coolant or simply condensation burning off. It does sound like valve stem seals. Very common in older Chevys. Another good test is while driving at a steady speed, back off the gas. Let the car slow down under compression braking, then step back down on the gas. A puff of smoke upon reapplication of the throttle, is a classic valve seal symptom. How healthy is the rest of the engine? Have you done a compression check? On a car this old, it may be time for more. I just finished the valve stem seals on my car.
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Joined: Apr 2004
Posts: 62
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From: Fayetteville NC
Re: Smoke Cloud (CFI-EFI)
I haven't tried letting off and hitting it again while driving, but at idle, if I rev it I get a puff of smoke. As far as I know the rest of the engine is ok...I haven't really done much to check it out. I haven't done a compression check. The engine idles real smooth for a couple of seconds, and then a just a little rough for a second, and back to smooth...in a cycle like that. It used/leaked about a quart of oil in 2 weeks. It looks like it is leaking some around the head gaskets, and maybe some around the oil pan or drain plug.
Race Director
Joined: Sep 2000
Posts: 17,298
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From: The Top of Utah
Re: Smoke Cloud (my1st_vette84)
The head gaskets aren't leaking oil. Probably it's the valve cover gaskets. Possibly the manifold end seals. Once you get the top end leak free, may be the leaks down below will stop. Gravity???
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