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CLK550 Mystery Oil Leak

6662 Views 11 Replies 3 Participants Last post by  rudeney
Almost every day, I find a small puddle (maybe a teaspoon) of oil under the car. It's basically right under the left side catalytic converter. It seems to happen after driving. I've removed the bottom engine covers and tried to find the source, but I can't. I see it on the steering column universal joint and the left cat (I sometimes smell it on the cat while driving). I see no signs of oil around the valve cover or even the head. I think I might see traces of dampness around the top of the exhaust manifold, but it's not wet enough to be leaking this much. Any ideas?
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OK, so this is now resolved. The part is called a "cam plug" and there are two of them on the back of left-bank valve cover. My leak was on the larger one (about 2.5" in diameter) that's behind the intake camshaft. There is also a smaller one (about 1" in diameter) behind the exhaust camshaft. Both of them together were $14 retail. I went ahead and replaced both. The guy at the parts counter told me it is a very common problem, and the symptoms are exactly what I had with it being very hard to find the source of the leak.
I think I have exactly the same leak...mine is on the driver's side. Crawled under the car, couldn't see anything at first, then noticed an oil drop up by the back of the engine...probably the valve cover.

From above, I can't seem to figure out how to get the engine cover off. The front section is easy enough but the back part must have some hidden clamps or something! How did you do it?

Also, was replacing the grommet (cam plug) easy enough? i.e. is it simply a screw off-screw on process?

THANKS for any help you can give me!!!
Engine cover just pulls up. It can seem stubborn because it fits tight over the air intake/MAF housing athe back. Make sure it reseats fully there when you put it back on.
Got it!!! Thanks! Now if I can only get my head behind to find the plug...:mad:
FYI "left" side = USA driver's side. And yes, you can use a mirror, but really, if you'll just use your fingers - run them down the back side of the valve cover. If they come back oily, it's 99% the cam plugs. They don't screw off - they just snap in place. Use a plastic screwdriver to pop them out.
Thanks to both of you! I think I can see/feel the larger plug. Oddly enough, the leak seems to have subsided but I'm sure it will happen again...after all, that's part of the "mystery", isn't it?!!!
Rudeney, thanks again for your help. One last any chance, do you remember the part number?
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