The cylinder head cover on my 1987 944S is always wet with oil. I cleaned and dried it when I changed spark plugs and wires, and it's got oil all over just a few days later. Is that a sign of some seal breaking?

Also, I found one spark plug well filled with oil the first time I looked into it, it hasn't accumulated much oil so far since I drained the oil out, but kinda worrying that time. What might have caused oil to accumulate there?

 

The oil is coming from the round black caps from the top of the cover. Those are vent caps. They vent any unnecessary pressure from the head. Any oil splattered on the underside of the caps will get pushed through by the pressure. If you have ALOT of oil on your cover then I would suspect something wrong. How many miles on your car and did you ever have you valve guides and seals replaced? You say there was alot of oil in one of the spark plug wells. How much oil? Was the tip of the plug fowled with oil? When was the last time you did a compression test? There could be several things contributing to extra pressure in the head.

 

I just refinished my 944S valve cover. There are doughnut shaped seals that keep oil from getting in the spark plug wells and yours are probably leaking-mine were. The only place I could find these parts by themsevles was Paragon.

 

just as there is a gasket that seals the outside edge of the cover, there are four gaskets that seal the spark plug wells. If the black plugs on top of the cover are leaking then when you take the cover off to replace the gaskets remove the plugs, they are held in with snap rings, and replace the o-rings that seal them to the cover. You will probably find the o-rings to be about as flexible as cast iron. If you do take the cover off it would probably be worth your while to replace the seals between the bolts and the cover also.

 

My '87 does exactly the same, a little oil from the rear black cap after each drive. I was told by a Porsche mechanic (who owned an S) that all the seals for the cover can be obtained in a single kit for ease.

Anyone considering changing the chain tensioner at the same time? My car is on 47K miles and I can't decide whether to wait till 60K.

Chris

 

Great info guys! I will make sure to refer back here when I need to take the cover off.

When I said there was a lot of oil in one of the spark plug wells I meant that the top of the spark plug is barely peeping out of the oil, so that's like more than 2 inches deep of oil?

Right now it's got 172400 miles on the car, and from the PO, he never touched the engine other than belts in the 7 yrs 90k mi that he owned it for. (sounds like the tensioner should be done too)

Oh and as for compression, it was actually for a compression test that I took out the spark plug wires and found the plug drowned in oil. The plug tips were oily, but that was also from the oil that flowed through when we took out the plug.

The compressions came out at 220, 230, 220, 210. That seems very high compared to the 951s but I haven't been able to find any numbers for the S. Do you guys think these are normal?

 

Actually, could the high compression indicate very high pressures so that's why the pressure has to be relieved, leading to oil spurting out of the relief caps?

What kinda problems could cause high compression?