Oil leak

Hey all, I've got a minor oil leak that I think is coming from the right side valve cover gasket. A mechanic friend of mine told me it is more likely to be a seal (o-ring) around where the coil packs connect to the spark plugs. This sounded logical to me as I am feeling an occasional hesitation under hard acceleration (like there's any other acceleration for a Porsche). It feels like a miss fire, maybe oil putting out a spark from time to time? Can anyone venture an experieced opinion on this one? Thanks

Sounds like an RMS leak. You might want to search the board for this one as it's pretty common, unfortunately.

If it is under the right side valve cover gasket and not the center of the engine between the engine and transmission then it is likely the valve cover gasket not the RMS. A good dealer will check both when he fixes one. Your dealer can also hook up his scanner (PST2) and check for misfires etc.

Thanks for you input. It is definately not under the center of the engine, rather under the the 3 coil packs on the right side of the engine. I am 99 percent sure it is not a RMS, so my question lies in whether it is the valve cover gasket or the o-rings that I previously mentioned. According to a mechanic, valve cover gasket failures are rare on 996's and the o-rings that keep oil from flooding the tubes where the coil packs enter the engine are fairly common causes of a leak. Has anyone had this problem?

There is a TSB for new o-rings on the oil protection pipes (early 99) and I have personally had the valve cover gasket (exhaust side) replaced on my car (for leaks).

Hard to tell over the internet, but it sounds like you are talking about the spark plug tubes which do have O-rings. And they do leak oil. We discussed this on RennTech. Jeff http://www.renntech.org/forums/index...st=0&#entry418

Tool and Loren, Thanks so much for your posts, I think we've found the culprit. My 99 is an early build, so I will actively consider the valve cover gasket as well. Seems like a not so hard DIYS fix, especially since I have the very good fortune to have inherieted a lift. If that doesn't work, then it's on to the valve cover gasket, either way thanks again!

One quick question, I'm going to attempt the repair myself (I'm hoping it's the o-rings on the tubes), can you comment whether it's necessary or not to drain the engine oil?

The M96/01 hasn't got valve cover gaskets, the valve cover is sealed with Drei-Bond, a silicon-based sealant. Drei-Bond has been replaced with a different sealant in newer engines. Re-sealing the valve cover is much more involved than just changing the pipes. The tricky bit is taking off the valve cover, because it also holds the camshafts in place (there is only one additional internal bearing where the chains are). The garage would first remove the pipes and use these holes to hold down the camshafts. Also, you have to be very careful not to damage the surface when cleaning off the old Drei-Bond sealant. It doesn't come off easily at all. As I said, Drei-Bond has been replaced by a different sealant (some black stuff, Drei-Bond was white/translucent), so you want to find out what it is and get some. It can be done, but it's not straightforward. Cheers, Uwe

The newer large end o-ring is red in color and made of material containing silicone (p/n 999 707 215 40). The former large end o-ring (black) should be replaced with the new red o-ring. The small end o-ring (p/n 999 707 343 40) is also changed as it has a new part number. Note: You do not need to drain the oil. You may get some leakage so be sure and top up when you complete the job. Also, the tubes will come out easier if the engine is warm (not hot and not cold). Another note: When removing the o-ring from the oil protection pipe, be careful not to damage or scratch the o-ring groove.

Loren, Do you think it is necessary to drain the oil to change the o-rings?

No, just top it up when you are done.