Leak source help needed
 

Ever since a rebuild a few years ago I have been having a leak that I have decided needs to be stopped. As shown in the pictures below it would appear on the surface that it was coming from the chain housing to engine case joint. However as we all know that doesn't tell the real story. So I cleaned it up and notice after a day that it is dripping down to that spot from somewhere else above. Now finding where somewhere else is, is where I need your help. The leak continues even as the car sits for months untouched, so it must be from somewhere below the engine case oil level. It can easily leak a quart or two after sitting for a month. After some cleaning and investigation I am fairly certain it is not from some of the common spots. The oil appears to come from behind or above the cooling tin on #4. The best I can tell there is no leak between the cylinder base and the engine case. The oil seems to run down the back (between the chain housing and the heads) of the chain housing. Now for a few questions:

We often hear about rocker arm seal leaking; do the bottom ones cause the same kind of leak as the top ones? The reason I ask is the lower valve cover covers the entire surface and doesn't have the cut out areas like the top ones. I see no oil on the outside edges of the lower valve cover or the top ones for that matter. I have checked the top rocker arms for torque and they seem correct. I have not as yet checked the bottoms. I do have the RSR seals in the rocker arms. Can this cause the leak as seen below?

Could it be the gaskets and seals between the chain housing and the cams? Is the oil level that high to cause a constant leak?

Any thoughts are appreciated before I start taking the chain housings apart and the related re timing of the chains.

Rob

http://forums.pelicanparts.com/uploa...1290990047.jpg

http://forums.pelicanparts.com/uploa...1290990086.jpg

http://forums.pelicanparts.com/uploa...1290990114.jpg

http://forums.pelicanparts.com/uploa...1290990146.jpg

I am no expert. Thinking out loud here and not professing.

I am not convinced that the leak has to be below the oil line. After the oil settles from the tank into the case, there may be 7 quarts in there. Look at your case and imagine two gallons poured into it. I can't see it going up really that high.

I think the top oil level in the case is no higher than the viewable part of your leak.

Remember the chain housing can leak at the cam seal, in addition to where it attaches to the case.

I had a leak with the exact symptoms you describe; it would leak on its own even in weeks of not starting the car.

I opened up the chain cover expecting to do a cam seal; It turns out the (stud, standoff?) that is the pivot point for the idler arm is pressed and epoxied into the chain housing. The epoxy failed and oil was escaping out behind it, and it looked a lot like a cam seal leak, but was closer to the center of the engine than a cam seal leak.

Even worse, it means that the tensioner idler arm was flopping around and basically on a course to disaster, and I REALLY dodged a bullet finding it when I did.

My soltion was a new chain housing $$$ :mad:

Check out Grady's post #4 in this thread:

http://forums.pelicanparts.com/porsche-911-technical-forum/434694-cam-tower-area-oil-leak-diagnosis-repair-qs.html