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Leaking from the driver side. Replaced with it with a GM gasket back in November. Highly doubt the gasket went bad that fast. I remember seeing the SMALLEST crack where the gasket goes along. Could that be why the leak is back?
Yes - it's possible that there is leakage along that crack - but assuming that you're talking about the LT1 Center Hold down valve covers - there are other potential issues.
Pull the valve covers off and using a good straightedge check the area that the gasket sits for anything that isn't nice and flat. If one part of the sealing area isn't flat - make it flat. I'd suggest a very small amount of sealant (RTV) in that area where you think you saw a crack - that should prevent leakage there. Also check the area on the heads where the gasket seats - sometimes there is some crud that gets between the gasket and the head and that is known to cause leaks.
The early LT1's had magnesium valve covers - so I don't recommend going nuts tightening the valve cover hold downs - but tighten them evenly and work from the center outward. It's Ok to go a bit higher than the 71 in lb (6 fl lb) the factory recommends....
If leakage persists - see if you can figure out where it's coming from and use a little RTV in that area.
Also, dont use any kind of rtv, etc...Those rubber gaskets get installed DRY. No oil on heads,gasket, or valve covers to seal well....And Dont over torque.
Center Bolt valve covers can spread at the mating surface if over-tightened. Probably a little more so on the 93-96 composite covers than the earlier magnesium ones.
Pics. First two pics showing where the leak is. Then, showing the crack I was talking about. Still haven't checked if it sits flush against a straight edge.
Here are some pics. This was the most flat, straight thing I could find. Also, I noticed in some areas, the gasket doesn't sit completely straight. What I mean is, it's kinda "wavy". The valve cover itself seems to sit flat. I did find a few more small cracks.
OK - In my opinion - you have now found the problem. Those cracks are not "small" cracks - they are decent sized cracks, and could easily cause leakage. If I were you - I'd be looking for replacement valve covers. (Any of the center hold down style covers should work - as long as they physically fit (meaning they don't interfere with other accessories - so either look for a used one on your favorite site used parts site - or buy a new set of the plastic ones. I'd get new gaskets as well - those look a bit stretched....
Why it cracked - probably over tightened at some time in the cars past (maybe in an attempt to stop the oil leak -you're now dealing with), magnesium is very light - but it does have a propensity to crack....
OK - In my opinion - you have now found the problem. Those cracks are not "small" cracks - they are decent sized cracks, and could easily cause leakage. If I were you - I'd be looking for replacement valve covers. (Any of the center hold down style covers should work - as long as they physically fit (meaning they don't interfere with other accessories - so either look for a used one on your favorite site used parts site - or buy a new set of the plastic ones. I'd get new gaskets as well - those look a bit stretched....
Why it cracked - probably over tightened at some time in the cars past (maybe in an attempt to stop the oil leak -you're now dealing with), magnesium is very light - but it does have a propensity to crack....
I agree that those cracks look like excessive tightening. There is also one spot that looks like someone pried up on it at some time.
I see Proform sell a set. They are 1/4 inch taller than factory. Not sure if that will work with my coil pack setup. As it is now, the coils sit pretty high.
I'm not sure it is the valve cover. Yes, it has cracks. They look big on pics, but really aren't that big. The biggest crack, is actually in a spot where it doesn't leak. It leaks onto the head, left side of the head. I'm sure you guys are just annoyed as I am. But here are some pics. And yeah, was able to put the gakset back on. Would hate to buy new valve covers, and still have them leak. Don't even see why it leaks. Everything sits fine. Even sits flush with gasket in place. Shown in last two pics.
Just wanted to show you guys the difference. First two pics are of the valve currently on my car. Not completely straight where the gasket goes. Best pics I could get. Will this new valve cover stop the leak? I hope so. Ended up buying a pair on ebay. Should put it together Saturday or Sunday.
02-17-2018, 02:56 PM
Valve cover gasket leak, again
