Is this really true ???
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Burning Brakes
Joined: Mar 2006
Posts: 753
Likes: 241
From: New Hampshire
Is this really true ???
I was sitting at a bar last night talking about how I needed to put new valve seals in my C4 before I sell it due to the puff of smoke I get every time I fire it up. A guy sitting next to me perks up and says "just put that synthetic oil in and you wont get that smoke ever again. I told him I had never heard that before but would definately look into it. Is this true ??
Thanks Dino
Thanks Dino
Safety Car
Joined: Jan 2006
Posts: 3,940
Likes: 42
From: shavertown Pa.
guide seals
If you are getting a puff everytime you start, then go ahead and put the seals in, if it's only doing it now and then don't worry about it, my 88 used to puff every now and then, and so did my 94.
As far as synthetic stoping that, I wouldn't hold my breath, synthetic will get by bad guide seals, just as easy as regular oil, you might want to try going to 10-30, this may help, and these engines run hot enough to support the use of 10-30. unless you leave you car outside in below zero weather, you don't really need to use 5-30.
I use 10-30 in my Z, and in my 05 silverado, and 2 jeeps, all synthetic.only 1 jeep stays out side....
As far as synthetic stoping that, I wouldn't hold my breath, synthetic will get by bad guide seals, just as easy as regular oil, you might want to try going to 10-30, this may help, and these engines run hot enough to support the use of 10-30. unless you leave you car outside in below zero weather, you don't really need to use 5-30.
I use 10-30 in my Z, and in my 05 silverado, and 2 jeeps, all synthetic.only 1 jeep stays out side....
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Melting Slicks
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One thing I have found to actually work is if there is just a small amount of smoke, try using the castrol high mileage oil, it seems to help condition the valve seals and stop the oil leaking by, how long this solves the problem I dont know, but it worked on my 84 chevy truck with 137k miles and my 91 firebird with 140k on the clock.
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Melting Slicks
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From: Oklahoma City Oklahoma
For some unknown reason, when you change a high mileage engine to synthetic oil, you'll also develop leaks you never had before.
A puff of smoke on startup is really a non-issue, in fact, pre-LS1, I don't think there was a SBC engine ever built that didn't eventually do it. As long as it clears right up, it probably isn't that big of a deal. Another thing that causes smoke on startup is clogged drain backs, and has nothing at all to do with valve seals.
I was always told that smoke on acceleration = rings, and smoke on deceleration = valve seals.
A puff of smoke on startup is really a non-issue, in fact, pre-LS1, I don't think there was a SBC engine ever built that didn't eventually do it. As long as it clears right up, it probably isn't that big of a deal. Another thing that causes smoke on startup is clogged drain backs, and has nothing at all to do with valve seals.
I was always told that smoke on acceleration = rings, and smoke on deceleration = valve seals.
Le Mans Master
Joined: Nov 2006
Posts: 7,215
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From: Orlando FL
Most advice that is drawn in a bar is 
this is no exception, going to a full synthetic on high milage engine = bad plan. The high milage oils will help, I wouldnt worry about it. If it bothers you I would change the seals. If you are going that far pull the heads and do a valve job and check the spring tensions and replace the weak springs.. Good luck
this is no exception, going to a full synthetic on high milage engine = bad plan. The high milage oils will help, I wouldnt worry about it. If it bothers you I would change the seals. If you are going that far pull the heads and do a valve job and check the spring tensions and replace the weak springs.. Good luck
Safety Car
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The synthetic does not fix the seal problem.What happens is that synthetic,when burned,does not smoke like regular oil. Used car dealers have been doing that trick for years.
Racer
Joined: Aug 2001
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From: Chelsea MI
I had a Chevy PU with a 350 that would smoke on start up. An automotive engineering friend of mine suggested cleaning the oil return ports in the heads. It worked ! Very easy to do, just get some pipe cleaners (the kind for tobacco pipes ) , you can do the job in about an hour.
Le Mans Master
Joined: Mar 2006
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From: Lino Lakes MN
My old c4 puffed a little smoke at initial start up, never blew any oil and never burned any oil so was never a concern. I've never seen a early c4 with more than 50k on it that didn't, a couple of old timers I talked to used STP oil treatment like every other oil change with some success but, I didn't like the idea of putting honey weight oil in my crankcase.
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From: Anthony TX
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An old timer once told me:
Ya know what STP stands for? Stop That Pounding!!!!
Might as well pour a quart of 90 weight in there if your going to use that stuff! My brother purchased a Cutless once without doing any checking or investagteing. It ran pretty good until he changed the oil. It smoked so bad that it was undriveable!
Fortunaly for him we were able to pour some top cylinder oil in each cylinder, let it sit for a few days (Got the rings to unstick) and we also had to change the valve guide seals. After all of that, it really did run good.
BC
Ya know what STP stands for? Stop That Pounding!!!!
Might as well pour a quart of 90 weight in there if your going to use that stuff! My brother purchased a Cutless once without doing any checking or investagteing. It ran pretty good until he changed the oil. It smoked so bad that it was undriveable!
Fortunaly for him we were able to pour some top cylinder oil in each cylinder, let it sit for a few days (Got the rings to unstick) and we also had to change the valve guide seals. After all of that, it really did run good.
BC
Burning Brakes
Joined: Oct 1999
Posts: 836
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From: Colorado Springs, Colo., USA
My 87 would throw a little blue smoke on fire-up, when I solid it at 36,000 miles a couple of years ago. I was advised by the Corvette Center -- an independent Corvette service shop I use -- that it was normal for L98 engines to do so, and unless the smoke was truly significant, more than a "puff" to forget about it. Using 10 - 30 in the warm weather months helped, too.
