mferris

1995 911 with OEM valve covers

Aargh - just finished my Thanksgiving project of replacing both lower valve cover gaskets and replacing the lower grommets on both timing chain covers. In the process I discovered that the chain tensioner cover (the right one obviously since that one is on the bottom) needed a new gasket I think - so I figured I have to go back in and do that once it arrives - but I think I can get to that without removing the mufflers/etc. again.

However, I ran an experiment and used a bead of CurilT only on the Right (passenger in the US) side lower cover and did not use any on the left side. I was very careful on both sides in tightening in sequence from center to only 10nm. My experiment either failed or succeeded since the Left lower valve cover has several slow drips still. Note that while I did *NOT* remove the heat exchangers - I did loosen, then retorque some of the bolts on the left side (the one with the problem) - but I don't see why this would cause leaks itself.

There are a few things I don't understand.

1) When I first started the car and once it warmed up - there was smoke coming from the heater exchange vents (i.e. the engine fan blowing air through and I had the cabin fan turned *OFF* and air was venting from the rectangular vents. Why would there be smoke there?

2) The lower 2 drips (coming from the access ports to the heater exhaust manifold hex bolts) in the picture were more pronounced when I first started and warmed the car up and revved it. Why would oil get into those ports? Is this related to the oil coming from the heater exchange vents in 1) above? I do not see how the few drips from the (non-CurilT) valve cover could migrate into the access points.

After letting the car sit for 30 minutes, and then restarting and warming it back up - I took the pictures below. The oil from 2) above is *not* as pronounced as it was the first time I warmed, even after revving the engine. Maybe 2) above was just liquifying some oil that had accumulated somewhere while I had the valve cover off overnight?

Regardless I'm going to redo the left valve cover gasket with CurilT this time, dangit.

71-3.0-911

Did you recently do an oil change? That oil looks awfully clean and if it's the right side, did you possibly spill some when filling?

If that is coming from the recently changed lower gasket, something is incorrect. They should not leak with new gaskets and proper installation.

95_993

The oil smoke coming from the heater vents is due to oil that got into the inside of the heat exchanger while you were changing the gasket. My guess is that while the heater hose was removed to access the valve cover, oil dripped inside while the valve cover was removed.

I always cover the opening with tin foil while I have to cover removed to prevent oil or anything else from getting into the heat exchanger.

P-daddy

This ^
Any residual oil will burn off from the HE and smoke should stop after your shakedown run.

mferris

Thanks - I took it out for a drive and it definitely didn't smoke as much as when first started. I presume it burned off most of the oil in the HE.

As for the leaks on the valve cover. I have no idea. They are not as bad as before and I didn't notice any visible smoke when I parked it after a 20 mile run. I'll have to look at it again in the next week. Maybe I have a warped (OEM) cover? It's better regardless. I'm about 8 months into the shakedown of this new car to me - so still fixing/adjusting things (today was the first day I got to drive after changing the kinematic clutch lever and it was *much* more drivable than before).

95_993

Are you sure new valve cover gasket is leaking or could it be residual oil that dropped down on your heat exchanger while changing? 20 mile isn't much and wouldn't burn too much oil off. I'd wipe it down really well and then see what you get. I doubt you valve cover warped,

mferris

When I ran my finger under the valve cover - (above the hot heat exchanger) there were several drips hanging from a few of the hex bolts that I had just replaced. There's a chance it might be residual - but consdiering the other side is completely dry, I'm guessing not. Regardless - it's better than it was and I have a lot more confidence in how to do this again (might not even remove the left muffler this time).

pp000830

MFerris,
Could it be:
https://993servicerepair.blogspot.co...eak-after.html
Andy

mferris

I guess anything is possible - although I have not had an oil change in a year, and the drips are on the left side of the engine (far away from the filters and filler tube). Since for some reason I cannot read the dipstick - the oil is very clean (1K miles since the oil change) and I can NEVER tell where it is on the dipstick - I am going by the oil level gauge on the dash to know when I should add some up (after a 30+ min hot drive if the needed does not exit the red section at a stop light - then I add a cup or two) - so *MAYBE* the oil is too full and dripping from somewhere else.

I'll just drive it for a while and see where things end up.

SonnyT

As I've gotten older I've started to use a blue shop rag to read the oil level on the dipstick. Also, if you keep the oil level towards the low side of the dipstick, it seems to reduce the drips on mine. And the big one for me was going to Brad Penn instead of Mobil synthetic.

mferris

I'll try a blue rag - I'm trying to use paper towel and even then I don't seem to be able to read it. I have no idea. Perhaps its the 5W-40 Pentosin HP 2 that I'm using and it's just too clear.

Matsuzaka

When my 96 developed a VC leak my Porsche mechanic friend advised me to buy billet aluminum replacement covers.
He informed me that often, on these cars with plastic VCs, gasket replacement will not stop the leaks because what really happens is that the metal insert where the bolts go comes loose in the plastic and that is the actual cause of the leak.

mferris

Interesting theory. While having more possible locations for leaks/points of failure is not a good thing - the metal inserts seem to be surrounded by seals themselves, so if everything is flush/sealed then I'd think the metal insert to plastic connection should, theoretically, not matter. This is a picture of the valve cover that does *not* seem to be leaking any longer (possibly in part b/c I used Curil-T2 on this one and not the other one).

Todynot

Did you use original OE seals or aftermarket version?

mferris

OE