Topic: engine oil leak
in Forum: C4 Engines
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Duncanville, TX - USA
Joined: 3/18/2009
Posts: 2246
Vette(s): 1985 Coupe-L98/Auto,Bright Red/Carmine.
1974 Coupe-L48/4speed, Medium Red Metallic/Black Deluxe.
No real "problem" areas for oil leaks...sometimes the oil just wants to be on the other side....
I would suggest cleaning the area well, and try to determine where the leak is coming from. The front seal can leak, as could the front area of the oil pan, where it wraps around the timing cover. Could also be a leak higher up(intake) that is wicking down.....

I would suggest cleaning the area well, and try to determine where the leak is coming from. The front seal can leak, as could the front area of the oil pan, where it wraps around the timing cover. Could also be a leak higher up(intake) that is wicking down.....
Joel Adams
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"Money can't buy happiness -- but somehow it's more comforting to cry in a CORVETTE than in a Kia"
It's close quarters, but yes.
Look close at the pan gasket. I just changed mine due to a leak at the front under the timing cover to block joint. Fel-Pro one piece gasket worked out fine. No more leak. I also changed the valve cover gaskets. There was a leak at the rear of left cover running down the back of the engine block. I had to use dye to find that one.
Good luck.
-- Mark


Late models have a tendency towards timing cover leakage. Unless is leaking bad, I'd live with it, as you have to pull so much stuff to fix it. Now if you plan on doing things like a cam change, timing chain swap, etc., then is the time to fix it since you have to take it off anyway. Just my opinion.
the lt1 for 95 has 3 seals on the timing cover,one for the water pump drive,one for the opti spark drive and one for the crank shaft,also the cover gasket and the oil pan gasket is one piece and the timing cover doesn't have a separate oil pan seal.opti spark seals are becoming common.have to remove everything to get to these seals,so if you do it,do all of them.if its a gasket leak,well be careful not damage to oil pan seal under the timing cover,or its an oil pan seal change.if you buy the timning cover gasket set,all seals are included,good luck.TLaVac
marks146 said:
It's close quarters, but yes.
Look close at the pan gasket. I just changed mine due to a leak at the front under the timing cover to block joint. Fel-Pro one piece gasket worked out fine. No more leak. I also changed the valve cover gaskets. There was a leak at the rear of left cover running down the back of the engine block. I had to use dye to find that one.
Good luck.
Can the oil pan gasket be changed with the motor in the vehicle? I have a 1986 C4 and it looks possible, but I know you have to be able to pull the pan straight down first to clear the crankshaft. Looks like a major job, looks like you have to remove the starter and some smog lines too. How long did it take you to change the pan gasket? I have access to a lift so that should make the job a bit easier, but always good to get the details from someone who has done it before.
One more possibility is the crank position sensor seal on the right side of the timing chain cover. It's an oblong weatherpack type, ribbed seal, remove the single bolt and it pulls out easily but both are a challenge to get to. A lot easier if you remove the right side engine mount bolt and lift the engine away from the cross member. Once out, easy enough to clean the silicone seal before then the fight to get the bolt started.

in Forum: C4 Engines
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