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Valve Cover Gaskets STILL Leaking!! Help!!

5K views 11 replies 7 participants last post by  AU2XR85.0 
#1 ·
Okay. I have about 30,000+ miles on my motor and I can not get the valve cover gaskets to stop leaking. I'm on my fourth set of gaskets for this motor and I still can't get them to stop! I'm at my wits end. Last time, I went ahead and sprang $25 on the rubber gaskets with steel cores, but they're leaking, too.

I'm tired of having to pull the upper manifold to change out these gaskets.

Does anyone know what I can do to stop this? It's embarassing leaving spots of oil all over parking lots and my driveway.

Thanks in advance...
 
#3 ·
Forget the rubber/steel gaskets. Did same thing; put 'em in bin.
Good sealant; make sure gasket surfaces are completely free of oil and dry when you refit gasket.
Use non oil based cleaner to clean. Overtightening can sometimes make problem worse.

I'm sure you've had a go at all that already. They're just some of the boo boos I've made.

Cheers
 
#4 ·
I'm running pressed steel covers- I have a set of aluminums, but the stock manifold is too low to fit them.

I've done everything I could to keep them from leaking- cleaned all surfaces thoroughly, new gaskets every time, and snugged them each, starting from the center. I'm at a loss.

I'll pull them and try some gasket sealer in the next couple of days, whenever I get a chance. Should I put it in addition to cork gaskets? Is that what ya'll are running?

Thanks for the help, guys.
 
#5 ·
I suspect you have warped or cracked valve covers. I allways use rubber gaskets, installed dry with clean steel mating surfaces and only ever had leaks from loose hold down screws.

Check the bottom surface of you valve covers on a perfectly flat surface next time theyr'e off.
Marshall
 
#6 ·
Thanks, Marshall. I actually haven't gotten to them, yet- I WAS fighting with my AOD, but I'm converting to a T5, so problem solved there.

I'll check the valve covers when I pull them, but how in the world would a VC warp? Have you re-used rubber gaskets before? How should I clean them if I re-use them? They don't have 3,000 miles on them.
 
#7 ·
You should never use a mastic on cork seals. It makes the gasket splay out instead of only down. The surfaces should be absolutely oil free to provide grip. About the only place on a windsor you would use any application on a cork gasket is some contact adhesive to the block at either end of the intake manifold.

And yes I know invariably guys use a sealant on the sump cork gasket, but they shouldn't.

You aren't, per chance, cutting off the tabs that locate into the cover are you?
 
#9 ·
When the bolts are over tightened the VC's gasket flange will distort due to more pressure around the bolt holes and less along the rail. 5 ftlb's is all thats needed
Fit the covers on heads with no gaskets to see if they sit nice and flat .If they have been over tightened they will make contact with the head around the bolt holes ,but not so much along the rails which is where any leak will occur.
Turn them upside down and rest the VC rail on a flat surface and slowly hammer them straight.
Coat one side of the gasket with adhesive then stick it to the rocker cover ,this side of gasket won't leak and will stop it moving when fitting the covers.
remember 5 FTLB's

Also have you thought about using a phenolic spacer in between the upper /lower manifold to raise it up enough to fit the alloy covers?
 
#11 ·
i old fella i know who used to build big block engines for boats told me once that getting cork gaskets to seal properly is hard but he said there is a way and i have used it several times with out any leaks.

1. clean both surfaces with metho or thinners, and slight roughen surfaces, repeat clean.

2. buy a tin of frost bright or silverbrite, paint cork with silver, only thin layer, allow to dry and recoat after 10mins, fit gasket, torque bolts to spec, DO NOT OVERTIGHTEN, as cork will split.

Allow several hours before starting engine, and hopefully there wont be any leaks. good luck.
 
#12 ·
Freshmeat said:
Okay. I have about 30,000+ miles on my motor and I can not get the valve cover gaskets to stop leaking. I'm on my fourth set of gaskets for this motor and I still can't get them to stop! I'm at my wits end. Last time, I went ahead and sprang $25 on the rubber gaskets with steel cores, but they're leaking, too.

I'm tired of having to pull the upper manifold to change out these gaskets.

Does anyone know what I can do to stop this? It's embarassing leaving spots of oil all over parking lots and my driveway.

Thanks in advance...

OK, i know a little trick that does the job and should last till the next time you pull the rocker covers off.

1. clean surfaces to be sealed with metho or thinners.

2. apply silverfrost or frostbrite to cork gaskets, allow to dry(10mins)and apply second coat.

3. just as the second coat gets sticky, fit gasket and torque to spec(5-7ft/lb)

That should do the job for you. good luck.
 
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