Rear main seal oil leak?

[mike sampsel]

After 4,000 miles since rebuild, I’m down my “final” oil drip. Thought it might be coming from the case or the forward stud, so I applied some (generously) Dow Corning 111. The oil looks dirty so it’s likely dripping of the front of the case? Oil is fresh some 6 months ago.

I’ll get some photos of the case when my endoscope charges.
Any ideas, and if it is the rear main seal, any harm in leaving it be? The triangle looked pristine when I last checked and I didn’t see a trail of oil from on high.

[john walker's workshop]

Mainshaft seal maybe?

[dannobee]

Does it smell like gear oil?

Isn't Dow Corning 111 a silicone lubricant, not a sealant?

[mike sampsel]

Originally Posted by dannobee

Does it smell like gear oil?

Isn't Dow Corning 111 a silicone lubricant, not a sealant?

I don't think so on the smell, but I can check again.

111 is not a sealant, but I thought it would yield a clue if its weeping from the rear stud or the case. Based on no to little change with vs without the 111, I'm assuming (perhaps incorrectly) its not seeping from the case seam or the stud.

Difficult finding oil behind the exhaust crossover pipe too.

[mike sampsel]

Originally Posted by john walker's workshop

Mainshaft seal maybe?

John,

There is definitely some grime up at the hole between the engine case and the trans.
Makes me believe it is likely the mainshaft seal. Given it is, as long as I do not let the oil level get low, the harm seems minimal to leave it as is a while?

Other than I wanted a drip free rebuild . Oh and the small of the oil getting on the crossover exhaust.

[proporsche]

Mike..it is really possible that your trans.t/o bearing tube is leaking -- just a guess now until you clarify if it is engine or gear oil.On the tube is a seal plus little O-ring many people do not know-or do not replace this one...

Ivan

[mike sampsel]

Originally Posted by proporsche

Mike..it is really possible that your trans.t/o bearing tube is leaking -- just a guess now until you clarify if it is engine or gear oil.On the tube is a seal plus little O-ring many people do not know-or do not replace this one...

Ivan

Hi Ivan,

I does not smell like gear oil.
The transmission was rebuilt by a pro at the same time, hope he replaced said o-ring. I'll double check the smell again. I do not want to get low on gear oil and not know it!


Update: Trans build list has a 999-701-359-40; 915 T/o Sleeve o-ring charge for $3.65. So I'll assume it was definately replaced.

Thanks

Oh and the seal I used was an Erling, did not use the one which came with the gasket set.

[proporsche]

Originally Posted by mike sampsel

Hi Ivan,

I does not smell like gear oil.
The transmission was rebuilt by a pro at the same time, hope he replaced said o-ring. I'll double check the smell again. I do not want to get low on gear oil and not know it!



T'hanks

That what i thought ,the work was all done by pro....but lets say the supplies of seal is questionable...personally i do not like V.R.engine gasket sets mainly the crank seal .I only use either porsche or black trimmed Elring....ask your tech what he used?

Ivan

[callard]

Use a black light on the drip. Some trans fluid fluoresces while engine oil doesn't unless you add dye.

[mike sampsel]

Originally Posted by proporsche

That what i thought ,the work was all done by pro....but lets say the supplies of seal is questionable...personally i do not like V.R.engine gasket sets mainly the crank seal .I only use either porsche or black trimmed Elring....ask your tech what he used?

Ivan

I did the engine, used the Erling seal, not the VR supplied one. Will see if I can find a black light. If it is the crank shaft seal, is it a serious enough issue to get fixed right away?

[mike sampsel]

Originally Posted by callard

Use a black light on the drip. Some trans fluid fluoresces while engine oil doesn't unless you add dye.

Anyone know if Kendall florescees?

[proporsche]

well.if it the crank seal you will be annoyed by the smell as you can tell it drips on the cross member
a lot of peeps drive with this leak but i`m sure you would not;-)
ivan

[mike sampsel]

Humm, I wonder if there is a “worthwhile” flywheel upgrade. This might make the effort to get to the crank seal more liked. Suspect the stock flywheel is hard to beat though.

[Flat6pac]

Mike, when you pull the flywheel, I can’t recall telling you to JB weld the end plugs of the oil gallies.
There is 3 plugs behind the flywheel. I chased a leak there in the past.
Bruce

[mike sampsel]

Originally Posted by Flat6pac

Mike, when you pull the flywheel, I can’t recall telling you to JB weld the end plugs of the oil gallies.
There is 3 plugs behind the flywheel. I chased a leak there in the past.
Bruce

Thanks Bruce,

Looks like you thought to tell me.

[proporsche]

Mike is it me or not, I do i see the seal too deep inside?
It should be flush with the case

Ivan

[proporsche]

like this Mike i just finished 1982 engine

[mike sampsel]

Originally Posted by proporsche

Mike is it me or not, I do i see the seal too deep inside?
It should be flush with the case

Ivan

Ivan,

Ouch, so maybe I pushed the seal in too far? This is the only pic I have.

[Rodsrsr]

Use factory Porsche seal, flush with the case.

[mike sampsel]

Originally Posted by proporsche

like this Mike i just finished 1982 engine

Ivan,

This is the Porsche seal?
Do you prefer it to the Erling now?

And if I replace the seal, is there a recommended sealant for the case seam, in case it's oozing?

Mike