Leaking Case.

[jberger]

Howdy all, I posted this on the type4rum also. I just recently finished a rebuild on my 79 2.0 FI, after installing it and running for a while it started to drip a small amount of oil from the engine to tranny joint. I figured this was the new oil galley plug my machinist put in so I pulled it and thought I could see a trail of oil from the plug down to the case seam and out, so I re-gooped the plug and reinstalled setting the plug tighter than before. Put the engine back in and again after about 15-20 min of running it started to drip. I left it for a day thinking it was could be existing oil I failed to properly clean, started it up the next day and after 15-20 min it started again, pulled it out the next night and I am unable to determine where the oil is coming from. The flywheel and clutch are dry, there is a film of oil on both the lower portions (just above the tranny flange between the two motor mount bolts) of the case and tranny with about 4" of the joint between the engine and tranny. I can not see any area of the case seam that looks as if it is leaking ( I used permatex aero sealant, brown ). Sorry to ramble it is hard to explain in writing. Any ideas? If the case is leaking at temperature on the lower rear horn is there anything I can do other than split the case again? The case was cleaned, checked for seal, and not pried on.

[ratwell]

Based on the number of reports, oil gallery plugs blowing is less of a cause of leaks than other sources IMHO. When they blow it's a bad day you'll never forget I'm sure. Assembly technique seems to count for a lot as you witnessed with your leaking oil gallery plug.

What I'd suggest is running the engine/transmission out of the bus by cranking it over with the starter and a battery jumper cable (remote starter is nice to have here). Run it long enough to build up maximum starting oil pressure and then some more (got a battery charger?). Separate the engine/trans and watch patiently for the leak.

There are only so many places it can come from:

- transmission (would be obvious)

- oil gallery plugs (I went the jb weld method; we'll see how it turns out.)

- or threaded plugs (how good is the fit? If the fit is good then I'd try loctite 518. I have little experience with it but the little I've applied reveals that it's thick, non very viscous and would make a better sealant than the goopy permatex you used).

- cam plug (split case or attempt jb weld)

- case parting line (split case. Apparently this is the place where the detal floss trick that Porsche engine builders perform)

- flywheel seal or flywheel o-ring (two possibilities. Was the o-ring replaced? Was the flywheel seal installed right? Was it put in a slightly different location?)

- assembly errors.

It's also possible you've got a groove in the hub of the flywheel and the flywheel seal isn't making enough contact. The flywheel could be toast if this is the case.

If it's ok, then the hub should be polished with crokus cloth before installation and the flywheel seal bore should be smoothed also (mostly at the case parting line).
_________________
'78 Westfalia CDN
'76 Doublecab
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[jberger]

Ratwell,
The original oil galley plugs are tight in fact the one that was removed was a bugger to get out. The threaded plug is a mercedes 16x1.5mm galley plug with tapered threads (kind of like pipe thread loose at first then gets tight) The flywheel as I stated is dry, as is the exterior of the seal, clutch, cam plug etc... all the oil ( and there isn't that much, maybe a drip every 30 sec to 1 min after 20 min of running ) is concentrated between the mounting bolts. If it is the case what is the floss trick you mentioned? I have also heard of using a type of locktite (green I think) that will suck itself into the case seam and seal it.
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[ratwell]

[jberger]

[whip618]

I have been experiencing the same type oil leak, and have pulled my motor four times since Dec. last year trying to find the problem. I
finally decided it was a groove worn in the flywheel from the main oil seal, even though the groove was only a few thousanths deep it
was enough to prevent the seal from doing it's job. I machined a sleeve from 304 stainless steel .005 thick and .400 long and shrunk it on the
flywheel seal area and it works perfectly, and hopefully will for a longtime. The outside diameter of the seal boss is 2.957 in. and you will
need to allow about .003 to .004 for a shrink fit if you want to have some one make you a sleeve, you cannot press a sleeve on that is this thin
or it will just crumple up and be of no use. these sleeves may available commercially.

The other method I was going to use if the sleeve didn't work was to machine a spacer .025 thick and place it behind the main seal so the
sealing lip is actually moved out .025, there is room to do this without the seal rubbing on the flywheel.

Phil

[jberger]

Whip618,

[whip618]

My flywheel was dry as well as the front of the case, the only sign of oil was a small trickle that ran from the lip of the seal down the seam of the case. The bottom of the bellhousing on the tranny was where all the oil collected. My oil leak was exactly like you described yours to be. I checked everything I could think of even the oil drain above and below the thrust bearing maybe being clogged and oil being forced through the seal. I didn't think it could be as simple as a groove in the flywheel but it sure was, now my 2.0L is oil leak free and its great.

Phil

[jberger]

I will check it out again tonight, but I could not see a trace of oil from the seal down the case. Worth a look though

[ratwell]

[jberger]

I took a good look at the seal and area around it when I pulled the flywheel and double checked it last night and it looked dry as a bone, no trace of oil or oil film anywhere. My flywheel does have a slight groove in it, however I measured the distance from the shims to the seal lip and the edge of the flywheel hub to the groove and the seal lip sits about 3/32" to 1/8" outboard of the groove. Shouldn't be a problem right? The flywheel was cleaned, surfaced, and hub pollished