Oil leak from aft housing bolt

[clark800]

I have some oil seeping out of one of the bolts on the aft housing when the engine is running. It's the lower of the two bolts on the vertical surface on the port side of the aft housing. The engine has a throttle cable bracket attached by these bolts, so they are screwed in slightly less far than they would be without the bracket, but they are tight at least.

I tried applying some Permatex #3 to the threads, but it didn't stop the leak. Is there anything else I should try?

[clark800]

Workaround

I realized that the leak probably isn't running along the threads, so sealing the threads probably won't help. I think the gasket on the fore side of the aft housing probably failed somewhere near the bolt, and the leak ran along the unthreaded portion of the bolt.

Although the ideal fix would probably be to take the aft housing off and install new gaskets, I decided to try an easier workaround. I just removed the lock washer from the bolt and after a 20 minute test there was no visible oil leakage vs. before after 10 minutes there was a small puddle. So it looks good for now!

[zellerj]

You will get more responses if you post pictures. Right now we don't really know where the leak is. From what I can figure, it is from a bolt on the transmission plate, or perhaps from the seal. Each would require a different fix. .

[clark800]

Photo

Good idea Jim, here is a photo showing the location of the leak.

[Dave Neptune]

Brackets bolted on to housings often leak past the threads because as you stated the oil comes through via the threads and the split in the lock washer. It is for this reason that a "star lock" type of washer which has no gap can be sealed and perform the locking of the bolt too. Kinda like you don't use lock washers on the head.

Dave Neptune