[xj40] OK, what's the secret to a non-leaking NEW valve cover gasket?

I apologize in advance for bringing this up as I know it’s been
discussed before, but I am looking for a bit more detail than I
have found in the archives. I have a '93 XJ6. I replaced the valve
cover gasket, 1/2 moons and plug seals. I can’t seem to get the
#$@%! gasket to stop leaking. It actually appears to be leaking
between the gasket and the cover as opposed to between the gasket
and the block. It seems to get worse if I tighten the bolts further
in an effort to ‘stop’ the seepage. Any specific words of wisdom
that any one could pass on would be much appreciated.
dws–
1993 Jaguar XJ6, 1981 Mercedes 380SL, 1999 Ford Ranger Sport
Eureka, CA, United States
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1 Like

In reply to a message from NorCalXJ6 sent Wed 27 Feb 2008:

1 … Are you using a genuine Jaguar OEM cam cover gasket?

Previous over tightening of the cam cover screws could have
distorted the cam cover. If you don’t have a suitable
surface table to check the flatness of the cam cover, borrow
your wife’s dressing table mirror (or similar suitable flat
glass surface) and after laying the cam cover on iy, check
around the periphery with feeler blades.

Before fitting the new gasket, ensure that all of the screw
holes are clean and dry - run the screws down the hole to
ensure they run freely to the full depth. Some of the holes
are ‘blind’ and a little oil down there will cause the screw
to ‘hydraulic’ and bind before the correct torque is applied.

I’ve never used a torque wrench on those screws - I’m
conceited enough to think I can judge the correct torque by
‘feel’ and I’ve never had a cam cover gasket leak after
evenly snugging them down by that method.–
The original message included these comments:

I apologize in advance for bringing this up as I know it’s been
discussed before, but I am looking for a bit more detail than I
have found in the archives. I have a '93 XJ6. I replaced the valve
cover gasket, 1/2 moons and plug seals. I can’t seem to get the
#$@%! gasket to stop leaking. It actually appears to be leaking
between the gasket and the cover as opposed to between the gasket
and the block. It seems to get worse if I tighten the bolts further
in an effort to ‘stop’ the seepage. Any specific words of wisdom
that any one could pass on would be much appreciated.


Bryan N, '91 Sovereign 4.0 L, RHD (exiled in US)
Cambridgeshire, United Kingdom
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In reply to a message from NorCalXJ6 sent Wed 27 Feb 2008:

Are you installing the cover gasket so the cup holds the cover?
The gasket cross-section is U-shaped and should grip the edge of
the cover. I used Permatex Blue RTV to hold it in place on the
cover. I also used RTV on the head/gasket surface all the way
around. And around the spark plug hole gaskets as well. Let the
RTV cure overnight before firing the engine.
Because of the angle of the engine, the right rear corner
accumulates a puddle of oil that rises above the gasket, so you
need to get a good seal in that corner more than anywhere else.–
The original message included these comments:

I apologize in advance for bringing this up as I know it’s been
discussed before, but I am looking for a bit more detail than I
have found in the archives. I have a '93 XJ6. I replaced the valve
cover gasket, 1/2 moons and plug seals. I can’t seem to get the
#$@%! gasket to stop leaking. It actually appears to be leaking
between the gasket and the cover as opposed to between the gasket
and the block. It seems to get worse if I tighten the bolts further
in an effort to ‘stop’ the seepage. Any specific words of wisdom
that any one could pass on would be much appreciated.


Pete 70 XKE (193K) 88 XJ6 (244K) 88 XJ6 (234K) 60 Mini
Severna Park, Maryland, United States
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In reply to a message from NorCalXJ6 sent Wed 27 Feb 2008:

After a couple of failed attempts, I figured out that you
only need about half the recommended torque to keep it from
leaking. My problem was that I was torquing to the
recommended spec and crushing the gaskets to the point of
tearing. There is no pressure to speak of inside the cam
cover, so all you need to do is stop seepage. Start wit half
the torque and work your way up about 1/8 turn at a time, if
you need to tighten.
R,
Gunner–
Gunner 94 VDP 159K+ miles-79 El Camino Royal Knight 235K+ mi
Hendersonville/Tn, United States
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the cover. I used Permatex Blue RTV to hold it in place on the
cover. I also used RTV on the head/gasket surface all the way
around. And around the spark plug hole gaskets as well. Let the
RTV cure overnight before firing the engine.

I installed mine absolutely DRY, must gasket to metal. I tightened
the bolts just a bit more than finger tight. It seals perfectly. You
dont have to honk down on it, the weight of the oil above the gasket
level is very light. Oils is lighter than water and the pressure of
water at a depth of 1 inch is less than 1 psi. It wont leak if the
gasket and surface is clean.On Wed, Feb 27, 2008 at 2:35 PM, Jaguarpete jaguarpete@aol.com wrote:


Jim Isbell
“If you are not living on the edge, well then,
you are just taking up too much space.”

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In reply to a message from Jim Isbell, W5JAI sent Thu 28 Feb 2008:

I think Jim has the key. The secret is that ALL the gasket contact
surfaces should be cleaned with lacquer thinner until they are
scrupulously clean and oil free, both the head and cover, then the
gasket needs to have a dab of rtv put at the point where the half
moons contact the level gasket surface and on the half moons
themselves. I had installed two gaskets, the second with Hylomar
HPV, they both leaked. I then cleaned everything, got the oil level
down in the head recesses to be sure it did not contaminate the
gasket surface and installed the new gaskets dry. It has never
leaked again.–
The original message included these comments:

I installed mine absolutely DRY, must gasket to metal. I tightened


Brian Caro 96XJ6 4.0 63E-TypeS1FHC 05 XJ8 4.2
Newport News, VA, United States
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