#8 nose bearing oil leak

[avsarinana]

Just had the engine fully rebuilt, i have a oil leak in the pulley area.. How common is this leak. Not sure if its the pulley seal or the # 8 nose bearing seal. hoping its not the nose bearing seal.

[DRACO A5OG]

Post a pic after removal of pulley.

[T77911S]

i have not had/seen one apart in a very long time. the last one was a 2.4T.
if I remember correctly the nose bearing had a rubber Oring. in this case it wore a groove in the case. the case was not machined (motor was being done by someone else) and so it leaked when it was rebuilt.
I was just a spectator in this deal.

[avsarinana]

the car is back at the mechanics shop for this oil leak... rebuilt motor is still under warranty.. other than that oil leak, car runs good and no other current oil leaks. Mechanic has taken it apart yet, to determine were the leak is coming from ?

Thanks!

[KTL]

It's more commonly the bearing insert itself, in terms of it's fit in the case bore, than it is the o-ring being a leaker. Still, if not careful when we set the case half in place, the o-ring can get pinched and that's a guaranteed oil leak.

The o-ring can provide only so much resistance to leakage because this area is actually under oil pressure where oil comes out of the engine case and goes into the bearing at a hole-to-hole location. Oil is delivered into the bearing insert to provide oil pressure/film at that bearing location, as well as delivering oil into the crankshaft for rod bearings. The crankshaft gets it's oil from #8 and #1 main bearing locations and internal passages send it to the rod journals for the rod bearings.

Here's a good discussion on it. General consensus nowadays, since the case bore is most likely not an exact precise fit around the bearing insert anymore, is that we put a thin layer of sealant in the bore to add an extra level of protection against leakage.

#8 nose bearing

I think often times people expect the leak to be coming from the radial seal that goes around the pulley snout. But a newly rebuilt engine is unfortunately more likely to leak from around the bearing insert and not from a new radial seal.

[Joe Bob]

I have the bearing repair kit if want it. I switched to higher single grade viscosity oil and it stopped.

[avsarinana]

The funny thing is that it doesn't leak while I'm out driving the car around, it will leak after I park the car and it cools down...

[Daves911L]

Probably leaking slowly into the bottom of the engine mount while driving, and dripping out after it sits.

I had this problem recently with an engine I rebuilt. Leaked obviously moments after startup First time I have ever had leakage at the #8 bearing. Baffling.

In this case, the problem was traced to use of a very old bottle of Loctite 574 (teach me to be a cheap SOB and never throw anything away). This stuff apparently has a shelf life. It did not "flow" to the correct thin-ness, instead curing as a relatively thick layer, and not allowing case halves to seat correctly. Problem initially most apparent around the #8 bearing, but would have soon led to more serious grief.

Unfortunately, correction required complete teardown.

[avsarinana]

Originally Posted by Daves911L

Probably leaking slowly into the bottom of the engine mount while driving, and dripping out after it sits.

I had this problem recently with an engine I rebuilt. Leaked obviously moments after startup First time I have ever had leakage at the #8 bearing. Baffling.

In this case, the problem was traced to use of a very old bottle of Loctite 574 (teach me to be a cheap SOB and never throw anything away). This stuff apparently has a shelf life. It did not "flow" to the correct thin-ness, instead curing as a relatively thick layer, and not allowing case halves to seat correctly. Problem initially most apparent around the #8 bearing, but would have soon led to more serious grief.

Unfortunately, correction required complete teardown.

My car started leaking the first week i brought it home from the pulley area( after full rebuild)... my motor was rebuilt by a reputable Porsche mechanic..he says it's repairable, he still hasn't got back to me on exactly what the fix is..

Once again that's the only leak i have. this is my fifth Porsche I've owned, and most do leak oil.. But when you do a full rebuild and all seals are replaced, you expect it not to leak oil.. ? for a little while.

I am concern, the car runs beautiful though.. just like a top.

Thanks!

[avsarinana]

Thank God, it was the intermediate shaft gasket that was leaking . Its been repaired.

life is good, later. Thanks!

[DRACO A5OG]

woohoo!

Make sure you tighten that crank pulley bolt to 135ft/lbs. if that gets loose, it will screw up your crank, kill dowel and the seal and probably cause #8 to leak. Ask me how I know