Strange Oil Leak In Bell Housing

[Tim Donahoe]

Today I pulled my engine to work on another issue, and I see a decent amount of oil in my transmission bell housing. I dipped my finger in it and it didn't smell like transmission oil.

So, I removed my clutch and flywheel and there was no oil whatsoever on the clutch pressure plate, the driven disc, or the back of the flywheel (the side facing the clutch). The engine interior was spotless, except for an obvious leak at the seam below the flywheel seal and the cam-plug area.

My question is this: how does engine oil get into the bell housing of the transmission and not get any oil on the clutch driven disc, pressure plate, or the back of the flywheel (the side facing the clutch)?

When my wife and daughter got home, I had them smell the culprit oil, then compare it to some of the engine oil I gathered from the engine, and also a sample of transmission oil. They both agreed that the culprit oil did not smell at all like transmission oil--but more like the engine oil sample.

So, I'm perplexed. Anyone else had this happen?

By the way, I replaced the transmission oil seal a few thousand miles ago--not that it matters because the oil does not smell like transmission oil, anyway--in case anyone thinks our noses are not bloodhound quality.

Tim

[Glenn]

#1 leaking flywheel seal
#2 leaking cam plug
#3 crack in case, usually behind #3.

Most likely the flywheel kept the oil off the clutch.
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[Tim Donahoe]

Hm?

I'll try another Elring flywheel seal and "O" ring.

But I have a feeling it's the cam plug, or somewhere in the vicinity.

I checked for crackes, previously, but I'll check again.

The interior engine face was completely dry--except at the cam plug.

I wonder, since there is little oil pressure around the cam plug, if I can seal that area with something, like silicone.

My main issue was not being able to figure out how the oil got to the transmission bell housing without oiling any part of the flywheel (both sides), or any clutch components.

Thanks, Glenn.

Tim

[Multi69s]

Tim as you mentioned, there would be minimal pressure at the cam plug. Even if you had 60PSI at the plug, and had a hole about 1/16", you would only have about 3.75lbs of pressure through the hole. If you think it is the cam plug, clean it good with some contact cleaner, then slater some JB quick weld over the plug. It will have enough bite to hold back that minimal pressure. Then when it is time to split the case, use a micro butane torch to heat up the JB weld, and it will pop right off.
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[Mr.Duncan]

Tim,

Anytime I have a new engine out for clutch work, or build a new engine, I clean the area first with brake clean.

I tend to put a nice bead of silicone from below the rear main seal (along the case seam) and around and over the cam plug.

Then smear it around smoothly with my finger.

I do this to avoid any future leaks should they happen.

No leaks so far.


If you need it, I can loan you my rear main seal installation tool. It lets you seat the rear main seal correctly and smoothly in its bore. It also is the type of tool that clears the crank dowel pins.

I think I spoke with you about borrowing my distributor drive pinion puller too?

Lastly, I can loan out my torque multiplier tool, so you can torque down the gland nut correctly. (instead of guessing)

Just shoot me a PM if you need it.

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[Tim Donahoe]

Thomas, thanks for the offers.

I have a Torquemeister (hot dog!( and the seal installer).

I'm finding so many little issues after pulling the engine that I'll do the 180 on the drive gear another time.

I just found out my fuel pump was leaking a little. Hell, the PO put a bunch of grease under the flange gasket--not under and inside the bottom of the fuel pump. I'm still shaking my head.

Also, I went to replace my manifold boots and lower manifold metal gaskets, and I came to the realization that you have to remove the manifold (raise and scootch it) in order to get the head flanges off. It's a good thing I have Wolfgang International here in town.

I'm taking a break now. While waiting for Wolfsburg West manifold boots (should be here tomorrow), I'm going to repaint my manifold? What are you guys using for this? What high-temp paint?

By the way, my heat risers were very clear (just a tad sooty) and my puel-pump flange came out easily--without the bottom cracking off.

So, my luck is running 70/30 today. Not too bad.

Tim

[Dwayne1m]

Tim, I painted the intakes on my 78 with just a Rustoleum silver metallic and then a clear coat and they are holding up just fine. Nothing hi-temp, but the FI intakes don't have heat risers either. I don't know how hot they actually get. Don't know if that info will help you or not.

[Eric&Barb]

Check an earlier pre-1968 VW workshop manuals and you will see images of acceptable oil leakage and the fact is the main FW seal needs a bit of seepage of oil to keep its edges lubed up and not burn due to friction there.

Easier way to check if it is time to change FW seal is how big the drip is under the VW when parked for 30 minutes. Up to a silver dollar size is fine. Anything much bigger it is time.

VWAG had the oil drain hole at about 8 O'Clock, which is above the lower ID edge of the FW seal. So when you shut down the engine all the oil in the passages and cooler flow downhill and some of this leaks out the FW seal because the FW is not rotating to pump oil back inside.

VW of Brazil improved the oil drain from that area by casting in a drain at bottom of the bore for the FW seal. Have personally drilled new drain hole near bottom in German engine cases.

You can see the German drain at left. Our added drain to the right of that (do avoid drilling into the large stud hole). VW of Brazil drain is to the right of that and dog legs down the case seam, between the two stud holes.

Showing same holes from inside view of engine.
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[Eric&Barb]

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[Tim Donahoe]

Well, my transmission bell housing appears to be somewhere between the two photos from Eric & Barb. The oil is on every square inch of it.

And I do not drip a silver-dollar-size dollop of oil while parked. Sometimes, there is no oil at all; other times, about a nickle-size amount.

I'm going to replace the flywheel seal and "O" ring, though. I'm there already. My Torquemeister knock-off made short work of that gland nut.

I re-inspected the area behind the flywheel, and the walls are way too smooth and new-looking to have any hairline cracks. I did notice the cam plug was sealed with an orange silicone-type material (RTV, I assume), but it's rather spotty; so I'm going to clean up the area really well and seal it with some silicone, like Thomas mentioned earlier.

However, the transmission appears to have a sort of squashed-cloud outline, about an inch or two under the trans seal. Hopefully that's not a hairline crack. It looks more like a complete circle, though--just squashed and having the outline of a cloud.

I also painted my new set of thermostat flaps. Apparently, I somehow managed to pull the curled flap-bracket that holds the rod, way out of whack. When I re-install the shroud this time, I'm going to have the wife help me, because I did have the rod in the inner head hole, before, after all. But when trying to install the shroud with the alternator attached--and trying hard not to damage the doghouse oil cooler, I was obviously unable to do this without bunging up the right-flap bracket.

I tried just pushing the rod in by itself, and it's apparent that a slight twist is required at first. So I'm going to try lowering and slightly turning the right side of the shroud, first, then the left.

Thanks for the tips, everyone.

Tim

[talljordan]

You could try slathering all the cracks and joints with some permatex aviation. Thats what I did when I did my rebuild. Haven't noticed any drips yet. Seems to hold up well and is reasonably easy to remove.
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[Tim Donahoe]

Upon closer inspection, my clutch driven plate shows a little lubricant on the interior face--up to a half inch of the fiber, that is.

So, I was getting some oil (it could be grease from putting too much grease on the splines or gland nut) somewhere besides the transmission bell housing, after all.

I have a spare clutch driven disc, so I'll use that one.

Tim

[Eric&Barb]

You can clean the disc with BrakeKleen. Yes, you want to use very, very little grease on those parts, so there is not enough to get onto the disc.
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[gjetson]

Tim...For what its worth....just got a letter from "Karnac, The Magnificent".
He tells me its leaking from the tranny side.

[Tim Donahoe]

Maybe Karnac has a better sense of smell than my daughter, my wife, and me.

It does not smell like transmission oil, seriously. And the transmission seal only has a few thousand miles on it. When I installed it, I did tap in in with a wooden dowel, instead of a long socket, however. But I think I got it in without breaking the "unseen" interior part of the trans. seal.

Tim

[Cusser]

Could the oil be from "initial leakage" with that new seal, and it sealed better after several driving cycles?
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[Tim Donahoe]

Well, cusser, you might be correct; but I suspect my engine oil got flung onto the transmission bell housing, due to a seepage around the cam plug (andd the straight seam near it).

I went ahead and changed out the flywheel seal, anyway. And I'm giving serious thought to changing out the transmission seal again. I'm in the vicinity, anyway. But that seal is a bitch to get out. If I do it, I'll get a deep socket or pipe to install it this time around.

Tim

[Volks Wagen]

[Tim Donahoe]

So, I installed a new Elring flywheel seal, and an "O"-ring at the back of the flywheel. I also cleaned up the cam-plug area really well and applied some silicone. After letting the silicone cure, I re-installed the engine and have driven it a number of times, since.

Not a drop of oil under the engine.

Knock on wood

Tim

[Mr.Duncan]

That's great news tim!
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