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Hi MFerris,
The OE covers are plastic and when torqued down using a torque wrench with new gaskets they don't leak. Warping is an issue with metal covers on older 911. The plastic covers conform to the heads when put on. The 993 covers have proven to be very durable.
Smoke at the cabin vents is from the burnt oil vaper being drawn through the engine fan into the heater duct by the heater blower in the engine compartment on through to the vents.
One can spend a lot of money chasing oil leaks on a 993. My rule is if it is not dripping on the exhaust and smelling bad or dripping on the floor and bothering you, let it alone.
Here is a couple of pages on oil leaks:
Damnit - did the drivers/left side lower valve cover gasket for the 2nd time (using another new gasket just to be careful as well as Curil-T2) and there was a pool of clean oil on the heat exchanger this morning after sitting for a week. I may have to go higher up (not sure if it's the timing chain cover or the upper gasket yet). Was hoping I was done.
Damnit - did the drivers/left side lower valve cover gasket for the 2nd time (using another new gasket just to be careful as well as Curil-T2) and there was a pool of clean oil on the heat exchanger this morning after sitting for a week. I may have to go higher up (not sure if it's the timing chain cover or the upper gasket yet). Was hoping I was done.
Looking at you earlier photos, oil pooling on the heat exchanger where it's at in your photos has me leaning away from the timing giver gaskets as they are too far rearward. It possible the upper valve cover as you noted which is tight but can be done or the gasket between the head and timing chain boxes...more involved. More pics of those areas would be helpful
I've replaced the upper seals a couple of times with varying degrees of success.
The last time I did them I also did the lowers with a lot of other stuff like plugs and leads.
Not all gaskets are the same. A set of uppers I purchased a well known dealer in the U.S. had a tear almost all the way through that looked like it happened when the seal was removed from the mould during manufacture. I live in Australia so returning the seal would have been an expensive exercise.
Check your seals for tears and cuts before you put them on.
Curil-T - wish I'd known about this stuff years ago. Last time I did the seals - several years ago - I used Curil-T and have not had a drop of oil leak from the covers.
Damnit - did the drivers/left side lower valve cover gasket for the 2nd time (using another new gasket just to be careful as well as Curil-T2) and there was a pool of clean oil on the heat exchanger this morning after sitting for a week.
Is the aluminum surface on the cam box smooth and gouge-free?
Did you thoroughly clean the valve cover, especially the groove the seal sits in? Are the aluminum bushings in the valve cover loose?
I used gaskets that I bought from Porsche. I never needed any Curil T or any sealant at all.
All four valve covers were bone dry, and they were that in the next year and the year after that.
Take your time and do it right. This is not rocket science!
Haven't had a chance to look closer yet - but my guess is that it is the upper cover that I did not replace. I drove around in 30-45 degree weather this weekend for about 30 min and didn't see any smoke after stopping (which had happened before doing the lower valve cover gaskets and the lower timing tensioner gasket) so the majority of the leaks are fixed fortunately.
I really don't understand. I've replaced the lower gaskets, including redoing what I thought was my one bad side - now both are leaking again. The oil is dripping from the nubs under the bolts (red circles) which is logical given those are the lowest parts of the covers. The arrow indicates leakage around the bolt itself. I've carefully torqued everything to 10nm, in order from center to the front and back (top and bottom), taking about 4 rounds to apply/tighten consistently. Used Curil-T2. I'm about to purchase new valve covers themselves just to see if that's the problem (99310511654 - but looks like these are $230/piece. I cannot see much from the uppers.
The oil is dripping from the nubs under the bolts (red circles) which is logical given those are the lowest parts of the covers. The arrow indicates leakage around the bolt itself.
The only way it can leak there is past the seal or if the bolt hole is open ended int8o the engine. Its been a very long time since I replaced my valve cover seals but those bolt holes should be not be thru holes.
I am the one that mentioned about the metal inserts coming loose from the plastic VC causing the leak.
If you think about that it makes sense. So, the insert is bottomed out by the bolt but the plastic can move up and down on the insert so the gasket and VC is not really pressed down so oil can leak around the gasket and leak out. Make sense?
Makes sense. I was thinking (hoping?) that since the seal completely surrounded the metal shaft area that no oil would sneak through to the metal shaft area; however, if it is moving some that could cause the seal to leak a little anywhere. Regardless - new valve covers are my next step I guess (even though the drips are greatly improved from before and there is no visible smoke, the smell in the garage is more than I'd like). I'll stick with OEMs for now.
I was thinking (hoping?) that since the seal completely surrounded the metal shaft area that no oil would sneak through to the metal shaft area; however, if it is moving some that could cause the seal to leak a little anywhere.
Look at the back side of the valve cover I posted. If the valve cover is bolted down and your seal does not leak, oil cannot make it to those aluminum spacers and to the bolts. Also, with the gasket in place, it sticks out about 1/8 inch past the valve cover.
Porsche never used any additional sealant, why would anybody unless they had a butchered sealing surface on the cam towers.
Generally agree which is why I’m confused as all get out that there are still leaks. This is the right side which seems to leak but a little less than the left side. Both surfaces seemed pretty smooth to me.
I have replaced my left lower gasket and the cam cover. I used new bolts and it still leaking around like three of the bolts. Its not terrible but it is still there and it never seems to be fixed.
Thanks for that - I'll try new covers (and gaskets) and then just live with it I guess. Before changing the gaskets, the smoke in my garage after a 30 minute drive was visibly flowing the open garage door in the sunlight. Now, there is no visible smoke - but the smell is a little strong for me (and likely people behind me while driving).
12-02-2023, 11:31 AM
