E46Fanatics - View Single Post - Yet another "Replaced Valve Cover gasket and still Leaks"
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Old 07-03-2012, 03:46 PM   #55
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Join Date: Jul 2008
Location: Pair O' Dice, USA
Posts: 593
My Ride: '02 330i
Originally Posted by alhayek View Post
I haven't done it again yet. I'm not sure if its the seals since the leak didn't come from there. would not replacing the seals cause a leak from the gasket? Speaking of the seals: How come the seals I ordered have a shorter neck than those installed on my car ? I used RealOem.com and made sure to use the same part number! Any ideas ?
I don't think that oil would normally leak from the seals themselves. The seals, and metal washers, sit between the upper flange of the cap nut and the valve cover. Since the cap nuts fit through the valve cover and bottom out, there is a space between the flange on the cap nut and the valve cover. The metal washer and the rubber seal fill that space at the proper thickness so that when you tighten the cap nut down, the rubber seal compresses and provides a certain amount of pressure down on the valve cover and gasket to keep it tightly sealed. Over time, the rubber seal may harden and stay compressed, so that it no longer creates enough pressure for the gasket to seal properly. This may be why it is usually recommended that the 15 rubber seals be replaced along with the VCG, especially if yours are the originals. This is my understanding of it, based on what I've read and what I've seen while replacing my own.

Now, I can't say that this is the problem in your case, and it may very well be that your valve cover is warped, or some other problem exists. but I think it is good practice to replace those seals anyway.

As far as the neck, I think it just fits down into the hole in the valve cover, perhaps just to keep it in place? I'm not sure, but I don't think a shorter neck would make any difference. Perhaps someone else has more insight as to the above and can add to it.

Last edited by josephi; 07-03-2012 at 03:57 PM.
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