Leak on a lower crankcase nut.

[Nine]

Hi all,

I have a minor leak on the nut I circled below. It’s at the flange on the bottom of my 996 Turbo engine. Can I remove this nut off it’s stud and seal it some how? Does it have an o-ring or something that may have gone bad?

Thanks in advance!

[Flat6pac]

There is just factory sealant on the center case, that’s a center line flange
The nuts are the distorted 13mm lock nuts that replaced the nyloc of the earlier motors
Bruce

[Nine]

Thanks Bruce. I’m seeing some oil weeping through the nut/thread there. Does not appear to be any oil on the other side where stud is. Is there anything I can try to stop it? Can I remove the nut and try some black rtv or something on the threads? Any ideas?

[Jeff Alton]

You could try to replace the washer and nut, it is a "stover" style lock nut like Bruce mentioned. But that area is sealed, as mentioned along the flange. You could possible try some sealant under the washer or on the threads of the stud, but ultimately, the case sealant is likely beginning to fail.

Cheers

[Nine]

Thank you Jeff, going to give the sealant a try. It’s a really small amount of oil that comes out. Should I try to back the stud out and put sealant on that as well or not mess with it?

Would be great if I could stop it though. Bone dry otherwise.

[twickes]

Jeff is right. The case sealant is probably breaking down. As a last resort, you could also try some Gasoila thread sealant. I've used it on an old leaking oil line. Worked great until I could find the time to properly replace it.

[john walker's workshop]

Are you sure it's not coming from the nut above? That one has a history of leakage.

[Nine]

I cleaned everything so I could figure out where the oil was coming from. I will double check again today but I’m pretty positive it’s coming from the one I circled.

Originally Posted by john walker's workshop

Are you sure it's not coming from the nut above? That one has a history of leakage.

[Peter M]

I had a similar leak on my 993 that I treated successfully with Permatex Thread Sealant. The oil was weeping down the bolt thread which surprised me. Removed and cleaned the bolt and nut, applied sealant to the thread, reinstalled and was all good.

[Nine]

This is what I’m hoping. Planning to try it this weekend!

Originally Posted by Peter M

I had a similar leak on my 993 that I treated successfully with Permatex Thread Sealant. The oil was weeping down the bolt thread which surprised me. Removed and cleaned the bolt and nut, applied sealant to the thread, reinstalled and was all good.

[Classic11]

I would take the nut off, make sure its all dry with no oil left and use Loctite 574 under washer and between washer and nut, plus on the threads. Other thread sealants might work also but it does not have to come through the thread. We use Loctite 574 for 15 years in manufacturing power shift transmissions (20000 units a year) very successfully between housings but also in threads. It will work.

[Nine]

Classic11, is the 574 product an actual thread locker as well as a sealant or just a sealant? How strong is it?

I was thinking about using permatex ultra black.

Thanks!

Originally Posted by Classic11

I would take the nut off, make sure its all dry with no oil left and use Loctite 574 under washer and between washer and nut, plus on the threads. Other thread sealants might work also but it does not have to come through the thread. We use Loctite 574 for 15 years in manufacturing power shift transmissions (20000 units a year) very successfully between housings but also in threads. It will work.

[targa72e]

574 is the original case half sealant used by Porsche (the orange stuff).

john

[stownsen914]

What are the two flat head screws in the side of the case, in the upper left of the pic? Is that some kind of repair? Wondering if the case may have been damaged in this area in its past.

[Nine]

I looked at a few undercarriage photos of 996 Turbo in bring a trailer and they all have those two screws.

Originally Posted by stownsen914

What are the two flat head screws in the side of the case, in the upper left of the pic? Is that some kind of repair? Wondering if the case may have been damaged in this area in its past.

[targa72e]

Those are not screws. That is casting information. If you look close you will see there are numbers on each side of the line. They often indicate the date of casting.

john

[Nine]

Just wanted to update the thread. Problem solved.

I removed the nut and cleaned very thoroughly the nut,washer, and stud threads. Then I applied a light amount of Permatex 59214 Thread Sealant to the threads and put it back together. Been almost 2 weeks now and it’s bone dry!!!

Thanks for all the replies everyone.