Oil leak at torque converter - PeachParts Mercedes-Benz Forum

BodhiBenz1987 · #1 09-19-2010, 12:04 PM

Well, after a day of perfect driving to Chad's PA GTG and back in my 87 (and a great time with great people!) I got home and a couple hours later discovered a small puddle under the car ... and oil seeping out from between the torque converter and engine, I guess from the rear crankcase seal. I had noticed it was a little wet there about two weeks ago (one of those weeks I was overseas), but assumed it was years of old oil being flung back there. I cleaned the engine pretty well Friday and the rest still looks clean and dry. But there's oil dripping quite a bit from that area. That part of the engine was always dry prior to two weeks ago. Perhaps not coincidentally, I did an oil change pretty close to the time it started ... maybe I overfilled? The dipstick last night showed oil a bit above the full line, but this morning is a bit below it. Should I try removing a tiny bit of oil to see if that helps the leaking? Or is it more likely just a coincidence that the oil change and leak coincided?
In case it's asked, yes I used the same oil as always, Rotella 15w40.

I'm about to put this car in drydock anyway to do the rear (got a nice big box of parts!), but kind of worried about the leak anyway.

Yak · #2 09-19-2010, 12:41 PM

If it's like the 617's, it's probably from your oil filter housing gasket. Check high on the rear part of the engine.

BodhiBenz1987 · #3 09-19-2010, 06:06 PM

Good call ... on further inspection, the oil is running down the side of the starter onto the engine, then TC housing. I can't really tell exactly where it starts, though ... the oil filter housing looks dry, or at least the part of it I can see connecting to the engine. The oil sensor sender unit is covered with oil, though ... could that be the culprit?
Thanks for the tip.

oldiesel · #4 09-19-2010, 06:43 PM

I had to replace the oil pressure sender on my 87td because it was leaking.I was doing the oil cooler lines at that time so the sender job was not too bad,i think to do it without removing at least one of the cooler lines it is going to be a pain in the neck job,at least it is an inexpensive part.I think it would be wise to order the o rings for the cooler lines just in case you really do have to take one or both off to change that sender. Don

BodhiBenz1987 · #5 09-26-2010, 05:15 PM

I replaced the sender last night ... it was a serious PITA, although not at all complicated. Just a matter of getting a wrench on the bolt. I ended up breaking it loose from underneath (needed a stubby 17mm), replacing it, then tightening it from above because I didn't have the hand strength with my arm extended that far from below. I think I got it pretty tight; it hit a point where there's no way to fit the wrench on it and still turn it, but I had to push it pretty darn hard to get it to that point so I'm guessing it's plenty tight.
Anyhow, there's nothing leaking down the side of the engine anymore and much less on the TC, but still a little dribble coming from the seam between the TC and engine, and looks like some coming out of the TC.

It's definitely oil, not ATF. It's very little, not even enough to drip onto the ground (so far). Will watch and see.

Random observation: The old sensor, when it came off, had a funny gaseous smell. My oil does not have this smell ... in fact I recently had it tested and there were no contaminants. Why did the sensor stink?

The new sensor also reads a little differently ... a hair lower at idle and seems more sensitive to little fluctuations. Pressure looks good though ... 3 bar at ~1200 rpm or above and about 1.75 bar at idle (when hot).

Oracle12345 · #6 09-26-2010, 07:27 PM

it could be your rear main seal or pcv system malfunctioning

vstech · #7 09-26-2010, 09:42 PM

the smell is cooked oil, mixed with various leaking diesel fuel from various places over the years. not to worry.
before you condemn the rear main, verify the VC is tight, and you have cleaned the daylights out of the motor! oil stays around quite a while.

BodhiBenz1987 · #8 09-26-2010, 10:37 PM

Quote:

Originally Posted by vstech

the smell is cooked oil, mixed with various leaking diesel fuel from various places over the years. not to worry.
before you condemn the rear main, verify the VC is tight, and you have cleaned the daylights out of the motor! oil stays around quite a while.

Ah, good. I'm so used to the various types of stink coming from my cars, I didn't know what to do with a new one.

It's definitely possible the oil that's pooling on the bottom of the TC now is oil that had gotten flung up there before and I wasn't able to wipe out. I'll have to get under there with a toothbrush and some Gunk. The neighbors are going to start wondering about me soon, if they aren't already ...

jt20 · #9 09-27-2010, 02:02 AM

if it does end up being the rear seal, there may be a quick 'n dirty way to bide some extra time before doing the deed.

this seal is rubber wrapped around a metal 'backbone' , if you will. It is pressed into an aluminum housing that is bolted to the back of the engine and oil pan.

typically, a groove wears into the crank where the lip runs. All you need to do is re-establish firm contact between the crank and seal.

It is my wacky belief that you may be able to press the seal into the housing a millimeter or so to make this happen. You should be able to accomplish this by using a slender, yet firm object that will allow you to access the seal from the lower port in the oil pan and the starter bore.

do it on a warm engine.

its 'out there' but it may be worth the few hours one day before you finally commit to a rather serious undertaking.