Has anybody experienced a valve cover STUD cause an oil leak?

[ZAMIRZ]

I'm at wits at end with this thing.

I have narrowed the oil leak down to a stud. Yes, a stud. The rear most lower stud on the passenger side lower valve cover. I've replaced the gasket with new hardware and there is oil leaking out of the stud hole onto the SSI heat exchanger. I don't know how this is even possible. You can see in the second photo that the gasket area is completely dry, but there is oil on the tip of the stud. I'm going to pull the valve cover again (3rd time now) as soon as the car cools off and see if I can make any sense of it. There is nothing above this with any sort of vapor on it or ahead of it. The valve cover gasket and sealing area is also completely dry.

Has anybody experienced this? What should I do? I don't want to crank down on the hardware, and I followed the normal tightening pattern starting in the center and working my way out criss-crossing up and down.

[mikedsilva]

I'm no expert....

if you remove just that nut, is the stud oily?

I think the only way oil can get down the stud, is if it leaks past the gasket that surrounds the stud. Maybe there is some old sealant that needs to be cleaned a little more from either the cam housing or the valve cover in that area...might be time to put a drop of sealant around the base of the stud to try and pin the leak.

good luck...

[Menmojo]

I've had the same problem. It's common. Make sure to use new nylock nuts. They are only good for one use in my opinion. If you continue to have a problem after using new nylock nuts you can use a removable lock title sealant on the threads. The big problem with this method is it makes a mess in the future.

[Reiver]

yeah, pull it and put a bit of 'right stuff' behind the washer. Nylocs can be reused here.....check their website.
I've reused nylocs numerous times with no issue in non critical applications.

[Tony V]

I had the same thing on both lower valve covers. Just one stud/nylock nut leaking on each side.
I put a little teflon tape around the stud and it solved the drip. I've heard that you can also clean the threads, add a dab of silicone to them and then tighten the nut.

[911pcars]

Valve cover gasket surface must be flat. If so, no path for oil to migrate past gasket to the stud.

Check flatness on a piece of float glass. If correction needed, remedy with some sandpaper on said glass plate. I sometimes use an easy-to-remove sealer (e.g. GaskaCinch) at problematic leakage paths.

Sherwood

[mca]

Get the reusable silicone gaskets. I switched to them 9 years ago after having the same problem. Even after full rebuild 7 years ago I continued to use them.

[sugarwood]

Does the nylock actually act as a seal? or just for nut tension?
Maybe you can try swapping 2 nylock nuts to see if its the nut that's allowing the oil to pass?

[ZAMIRZ]

Alright. Thanks to everyone who responded. I forgot to mention in my initial post that this only happens when the oil is hot. I use Brad Penn 20-50, and the oil temp gauge gets near the first skinny hash mark on the gauge when it starts dripping.

I always use new hardware (nuts and washers). I'm going to try the teflon tape and order the reusable silicon gaskets. I had already surfaced the valve covers as well using the 200 grit initially to knock it down and then the 400 to smooth it out flat.

I'll update you guys once I attack it again.

[grant lyon]

AFAIK, the nut/stud just clamps the VC cover down, and there shouldn't be oil exiting along the stud unless the gasket or interfaces sealing the inner side (where the oils is splashing around) are imperfect and not sealing. Look at the layout of the gasket vs. the studs to see what I mean. That said, if the gasket leaks (say, has squirmed) you can possibly get away with cleaning the VC, washer, and nut and coating these with a thin film of gasket sealer, torquing up to spec, and that may stop this unpressurized leak. BTDT, that same stud. Used Hylomar Blue sparingly. Sparingly because that is enough, and to not offend my mechanic's sensibilities.

[T77911S]

Originally Posted by mca

Get the reusable silicone gaskets. I switched to them 9 years ago after having the same problem. Even after full rebuild 7 years ago I continued to use them.

this is what I did too. never looked back. these things are GREAT. does not cost $$ every time you pull valve covers.

do NOT over tighten them, if they start to squeeze they are too tight.

I had a leak at the same spot. turned out to be the cam line just above it.