L98 Valve Cover leaks
Thread Starter
Burning Brakes
Joined: Jun 2003
Posts: 1,079
Likes: 1
From: Niagara Falls ON
L98 Valve Cover leaks
I put newly refreshed valve covers on my L98 back in the spring. I seems to be leaking alot of oil out of the passenger side. I can't remember what kind of valve gaskets I used. Any opinions on what I should be using?
Thanks
Thanks
Burning Brakes
Joined: Nov 2008
Posts: 995
Likes: 1
From: Naples Campania
This is kinda common for the centerbolt valve covers. A guy in my hometown used to do dirt track stockers. Any time he had a chevy with center bolts, he threw away the gasket and welded the valve covers to the cylinder heads.
Felpro is what I use on pretty much everything.
with both previous posters.
Felpro is what I use on pretty much everything.
with both previous posters.
Team Owner
Joined: Sep 2003
Posts: 20,179
Likes: 673
From: Freedom is never more than one generation away from extinction.
St. Jude '03 thru '24
Same problem with my 86. Passenger side.
I used a sandwiched rubber/steel from Felpro.
Cleaned up the VC real good and siliconed the gasket to the VC. (Let it dry overnite)
Then wiped the head surface clean, film coat of sealant on the gasket and install/torque.
So far........
I used a sandwiched rubber/steel from Felpro.
Cleaned up the VC real good and siliconed the gasket to the VC. (Let it dry overnite)
Then wiped the head surface clean, film coat of sealant on the gasket and install/torque.
So far........
Safety Car
Joined: Apr 2011
Posts: 3,660
Likes: 22
or if a gasket is used, make sure its a rubber. Always tighten the covers from center outward to ends. that seems to matter a lot on centerbolt covers.
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Michael S. Palmer
Race Director
Joined: Aug 2000
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a bit unconventional here. well, not really unconventional, it's the original procedure in the 85 FSM -- straight silicon sealer (RTV orange) without any gasket. i haven't used a valve cover gasket in some 20 years. the trick to leak-free, is to get both surfaces squeaky clean, and let the silicon sealer dry for 24 hours. pulling the valve covers, especially on an L98 is a bit of a pain - that's one job i don't want to do unless i have to...
Intermediate
Joined: Sep 2003
Posts: 27
Likes: 0
From: Taft TN
I recently used the rubber Fel-Pro gaskets on my iron head 86 and they are leaking worse now than the old cork gaskets were leaking before. These new gaskets seem to have a metal core, are ribbed, and seem thick. I just removed the left side last night thinking it wasn't positioned correctly, but the gasket was in perfect position and still stuck to the valve cover with the blue Permatex I used. The lower lip of the head and the bottom side of the ribbed gasket were covered in oil.
It was hard to get the nuts started when originally installing the covers with the new gasket. I was replacing the injectors at the time, so the covers set several days and I tightened the covers again before running it. I drove it a couple of times bringing the engine temp up, but it still leaked.
Has anyone else used these rubber gaskets on non-centerbolt covers?
I may just remove the gasket and go with the sealant method suggested above.
It was hard to get the nuts started when originally installing the covers with the new gasket. I was replacing the injectors at the time, so the covers set several days and I tightened the covers again before running it. I drove it a couple of times bringing the engine temp up, but it still leaked.
Has anyone else used these rubber gaskets on non-centerbolt covers?
I may just remove the gasket and go with the sealant method suggested above.
Melting Slicks
Joined: Sep 2010
Posts: 2,422
Likes: 202
i agree with the felpro perma seal silicone of all my TPI cars no leaks!!!! the old style outer hold down a nightmare... but felpro makes a perma seal version now!!! would have been nice if they made them 20 years ago
Last edited by THE 383 admiral; Sep 15, 2011 at 03:02 PM.
Burning Brakes
Joined: Nov 2008
Posts: 995
Likes: 1
From: Naples Campania
If you don't have one of these.
YOU ARE DOING IT WRONG!!!
Max G’s
Joined: Nov 2008
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From: Monroe OH
NCM Sinkhole Donor
Race Director
Joined: Apr 2002
Posts: 10,036
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From: Anaheim CA
I have been using the Fel-Pro rubber-steel-rubber sandwich style valve cover gaskets on my cast iron head '86 for several years. They seemed a little iffy on the seal and seemed like they didn't seal well when taken apart and reused. I recently adjusted my valves and bought new gaskets. I noticed the new ones have a solid block of plastic around the bolt holes to limit the compression of the gaskets. Maybe I was overtightening them.
I also left off the aluminum washers under the nuts because these gaskets are thicker than the stock ones. Interesting side note: the '86 cast iron heads are the only ones that used studs for the valve covers. All prior years used bolts.
I also left off the aluminum washers under the nuts because these gaskets are thicker than the stock ones. Interesting side note: the '86 cast iron heads are the only ones that used studs for the valve covers. All prior years used bolts.
Intermediate
Joined: Sep 2003
Posts: 27
Likes: 0
From: Taft TN
Thanks for the response.
I will look at my gaskets this weekend to see if they have the plastic piece around the bolt holes. I did not use the spreader tabs supplied with the gaskets either, but I did use the plug wire brackets under the nuts. Maybe I overtightened them too.
I will look at my gaskets this weekend to see if they have the plastic piece around the bolt holes. I did not use the spreader tabs supplied with the gaskets either, but I did use the plug wire brackets under the nuts. Maybe I overtightened them too.
Race Director
Joined: Jun 1999
Posts: 14,924
Likes: 9
From: Merritt Ils Fl
Thanks for the response.
I will look at my gaskets this weekend to see if they have the plastic piece around the bolt holes. I did not use the spreader tabs supplied with the gaskets either, but I did use the plug wire brackets under the nuts. Maybe I overtightened them too.
I will look at my gaskets this weekend to see if they have the plastic piece around the bolt holes. I did not use the spreader tabs supplied with the gaskets either, but I did use the plug wire brackets under the nuts. Maybe I overtightened them too.
Race Director
Joined: Apr 2002
Posts: 10,036
Likes: 346
From: Anaheim CA
Have you got part numbers for those two Fel-Pro gaskets?
I don't remember what color the ones I just put on are. I noticed today that I've got a small leak dripping on my #8 spark plug boot. I want to tighten the nut but it's buried under all the spark plug wires.
I hate valve cover gaskets. They always seem to have some kind of problem.
Cork - the oil eventually oozes through the gasket and leaks.
Neoprene - worked the best for me but I don't think you can get them any more.
Silicone - split lengthwise and were way too thick.
Rubber-steel-rubber sandwich - the first set I bought several years ago cost $35. Seemed high, but I wanted the best. I've had several sets on there since and they have been very iffy. Seem to require several heat cycles and retightening to get them to seal.
I don't remember what color the ones I just put on are. I noticed today that I've got a small leak dripping on my #8 spark plug boot. I want to tighten the nut but it's buried under all the spark plug wires.
I hate valve cover gaskets. They always seem to have some kind of problem.
Cork - the oil eventually oozes through the gasket and leaks.
Neoprene - worked the best for me but I don't think you can get them any more.
Silicone - split lengthwise and were way too thick.
Rubber-steel-rubber sandwich - the first set I bought several years ago cost $35. Seemed high, but I wanted the best. I've had several sets on there since and they have been very iffy. Seem to require several heat cycles and retightening to get them to seal.
