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Hi, I have a 1979 l82 corvette. Original engine. I have been battling with leaks for years, I have tried cork, thicker cork, rubber and fel-pro 1628 gaskets with no luck and then new valve covers. Last year I had the engine professional sealed and by the time I brought the car home I had leaks. Yesterday I had a corvette professional try and they are still leaking. I am at a loss. Maybe someone has an idea. I would really appreciate it. Thank you for reading. Jpl3
Do you have a PCV system connected? Is it working?
You've tried FelPro 1628 gaskets, and even new valve covers. Unless both of your heads are warped, my next guess is that something is pushing oil out of your engine.
Are your valve covers thick cast metal or are they the thin stamped steel covers?
I have had the same problem off/on for decades.
The best way that works for me:
Clean the cover and the head gasket areas area well with acetone first.
Use oil-proof adhesive on the cover and on ONE side of the cork gasket...
then left both get tacky and apply the cork gasket to the cover...
then SNUG the cover down on the head BUT do not over=tighten the retaining bolts or the gasket will "squish out of place".
Let it cure that way for 24 hrs.
The next day torque the retaining bolts to specs for a cork gasket. Check torque again in a week after car has been driven several times. (do not apply adhesive to the head surface/you want to be able to remove the covers when necessary
The other (outrageous=guaranteed) solution would be to have the gasket surface on the HEADs milled so there is enough flat surface for the gasket to seal against.
Are your valve covers thick cast metal or are they the thin stamped steel covers?
I have had the same problem off/on for decades.
The best way that works for me:
Clean the cover and the head gasket areas area well with acetone first.
Use oil-proof adhesive on the cover and on ONE side of the cork gasket...
then left both get tacky and apply the cork gasket to the cover...
then SNUG the cover down on the head BUT do not over=tighten the retaining bolts or the gasket will "squish out of place".
Let it cure that way for 24 hrs.
The next day torque the retaining bolts to specs for a cork gasket. Check torque again in a week after car has been driven several times. (do not apply adhesive to the head surface/you want to be able to remove the covers when necessary
I use Indian Head shellac gasket adhesive between the cover and the gasket.
Start all of the cover bolts/screws and barely snug them down.
I secure the bottom cover edge fully by gradually tightening up on the bolts.
Only after the bottom edge is secure do I snug the top bolts.
This ensures the bottom edge is not pulled by the top screws. No leaks.
Originally Posted by jpl31979
I tried adhesive to the valve covers the covers are cast
Not pressed or stamped. I think the heads need to milled.
What adhesive have you tried? If you aren't into Indian Head, a light smear of oil-resistant gasket sealer between the cover and gasket would work. Unless the heads' edges are actually damaged, milling would be pretty extreme.
Originally Posted by jpl31979
I have replaced the pvc.
. I bought it 2 years ago. How do you know if it is bad?
Pull the PC valve from the valve cover while the engine is running and put your finger over the end. You should feel a decent suction.
I don't know the numbers. But, the super expensive blue Fel-Pro valve cover gaskets work for me, with cast aluminium covers. I had a lot of issues with valve cover leaks myself. Triple check your valve covers are not warped or twisted. Just because L82 covers are cast does not mean they are flat and straight. I gave up on mine years ago.
I use a GM performance PCV valve. And silicone sealer on the cover side of the gaskets.
Definitely lay the valve covers on a known flat surface, in my case I have used door glass for my C10 that is perfectly flat, and make absolutely sure the valve covers are not bent. Also, with the 1628 gaskets, did you have them installed with the correct side up? Ask me how I know to ask that question, haha! My stock 79 L82 covers have leaked forever too, but I think the cork gaskets im using now are not leaking, fingers crossed!
Hi, I have a 1979 l82 corvette. Original engine. I have been battling with leaks for years, I have tried cork, thicker cork, rubber and fel-pro 1628 gaskets with no luck and then new valve covers. Last year I had the engine professional sealed and by the time I brought the car home I had leaks. Yesterday I had a corvette professional try and they are still leaking. I am at a loss. Maybe someone has an idea. I would really appreciate it. Thank you for reading. Jpl3
Put a steel edge on to (literally) see what shape they're in.
IDK about your cast valve covers but know that in the past on aftermarket chrome bits I've had to rough up the sealing surfaces to get the to stop leaking/weeping. Wire brush, sandpaper.
I used Fel-Pro VS12869R. I've had them on/off a few times. Zero leaks. No RTV involved.
Great advice by all. Here is your car replacing valve cover gaskets as recommended. https://www.corvetteforum.com/forums...ification.html
you will need longer bolts and you cannot overtighten. They will not leak if surface clean.
Post up pics of what you have! Good luck!
I tried adhesive to the valve covers the covers are cast
Not pressed or stamped. I think the heads need to milled.
You don't want to go down that road.
Removal of carb, distributor, wiring, Intake, exhaust, pushrods, heads, just for a start.
Then, rocker arms, valve-springs, valves, retainers and rocker studs.
Then big bucks for milling, even if you could find a shop to do that correctly.
If the op has cast covers, unless warped (which i have no idea how you would warp) should seal up flat with bolts.
love how the gaskets have standoffs that make perfect tension on seal.
My 70 LT-1 Cast Aluminum Valve covers did not leak even after 27 years.
And I periodically removed them to set the solid-lifter lash.
But you absolutely must install them properly.
I used thick cork, and a procedure like post #3.
Glued to the valve covers.
You don't want to go down that road.
Removal of carb, distributor, wiring, Intake, exhaust, pushrods, heads, just for a start.
Then, rocker arms, valve-springs, valves, retainers and rocker studs.
Then big bucks for milling, even if you could find a shop to do that correctly.
There are betters ways.
Very True...
milling is a last resort....unless you have a large piggy bank.
OR..if you are having the heads reworrked, then have the seal areas milled
On my original heads those valve cover gasket surfaces were as cast at the foundry. Kinda rounded off and a rough surface texture.
And I had a lot of trouble with leaking valve cover gaskets. About 7 or 8 years ago now I rebuilt my engine. At that point on went aluminium aftermarket heads. On these heads the valve cover gasket surface is machined flat.
And I haven't had any issues since.
Yeah it is amazing how oil-tight the newer engines are, with all their machined flat aluminum sealing surfaces.
A small 1" brown stain under the valve cover means a o-ring valve cover seal leak, on a Honda, at the dealer.
And they think it "must" be fixed!
Those guys would have a stroke if they saw the bottom of an old Chevy!
Ok, here’s my two cents regarding the cause of an untamed valve cover leak. When I bought my 73 the covers were leaking real bad. The PO had recently installed GM aluminum heads and aftermarket cast aluminum valve covers. He also retained the original cast iron exhaust manifolds. Upon my initial investigation I noticed that the bottom edge of the valve covers were catching on the top of the exhaust manifolds and not allowing the cover to rest on the gasket despite it being the thick style rubber ones. No amount of torque was going to close the gap between the head and covers. I filed some notches in the bottom edges of the cast covers to eliminate the mechanical interference rather than remove the iron manifolds and grind away the interference points on them. Mostly because they didn’t leak exhaust, and I didn’t want to press my luck. I see from your photo that you still have what appears to be the stock exhaust system on your car If so, check it out to see if the covers are actually resting on the heads. Hope this helps.
If you are thinking about milling the heads, just swap for some modern high-flow aluminum heads.
I have a set of previously non-leaking L48 valve covers, with a PCV breather, two sets of hardware to try, and road-tested 1628 gaskets, on the pay-it-forward thread. If those solve your problem, you'll know it wasn't the heads.
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Leaking Valve Covers
