Engine Oil Leak After F37

Timmaah! · **Posted:** Mon Jun 18, 2007 6:34 am

After 40 years of doing my own repair work (except for some exhaust and front end alignment) I made the mistake of having F37 done. There is no loss of power or fuel economy and the torque converter seems to lock up quicker and firmer. Computer was not flashed.

However, whenever I pull in my garage now there is about a silver dollar sized engine oil leak on the floor after it sits awhile. I got under it and the oil was on the bell housing and the transmission pan. I thought it might be the transmission lines but it is bone dry under the fittings and it is obviously diesel oil. It's not the oil filter. It always has wept a little at the return line from the turbo so I got under with a good light and took a look. It is dry before it gets to the bell housing but fresh oil appeares on the bottom of the bell housing and up from the bottom by one of the bolts in the bell housing where a drop forms. Does that make any sense? How can it not be leaking from the lowest point? Based on my experience, I don't believe that removing and replacing the transmission and torque converter could have anything to do with engine oil. I know it is possible to put too much jack pressure on an engine pan causing it to leak later but the engine pan is not leaking as far as I can tell. Any other ideas?

Cowcatcher · **Posted:** Mon Jun 18, 2007 10:39 am

This has been reported here before so someone will come up with and answer if you can't find it in a search. It seems to me it is a rear seal issue but do't recall.

Timmaah! · **Posted:** Tue Jun 19, 2007 10:09 pm

I am rethinking the “too much jack pressure on the engine pan causing a leak” possibility. I have changed a few rear seals where the seal is installed in a casting that bolts to the rear of the block with a flat lip extending down to the top of the pan. The seal is pressed into the casting and the seal is slipped over the end of the crank until the casting contacts the rear of the block. But, before the seal is pushed on to the end of the crank an alignment collar is placed on the end of the crank to center the seal or it is centered with a feeler gauge before the casting is tightened to the block. Then the pan is bolted to the flange on the bottom of the seal casting as well as the block itself.

Now comes the F37 and the jack that is supporting the rear of the engine while the transmission is being removed pushes up hard enough to compress the pan gasket and slide the casting that holds the seal upwards slightly. And, the seal having developed a bit of a set begins a slow leak. The leak is slow because it is not possible to move the seal casting all that much within the range of the bolt holes.

This has happened to a number of CRDs getting the F37. I don't believe in coincidence. There has to be something going on.

Timmaah! · **Posted:** Wed Jun 20, 2007 6:57 pm

Buzzzzzzzzzzzt! Wrong answer! I saw a parts diagram showing the seal housing and it is not constructed as in the description above. Thus this is not the reason for the leak.

Cowcatcher · **Posted:** Wed Jun 20, 2007 7:33 pm

I can't understand why others have not chimmed in here as I know it has come up before. Someone posted a photo about a year or more ago.

MightyCRD · **Posted:** Thu Jun 21, 2007 9:21 am

I've got the same problem with mine after having the TQ replaced last winter - real slow leak, bottom of the bellhousing. I was thinking it might have been a rear main (still haven't made the time to take it back to Jeep) - hmmm ... fixin one problem causing another .... gotta love modern mechanics!

tigafila · **Posted:** Thu Jun 21, 2007 8:24 pm

I posted another thread about my current tranny woes but I called the dealer today to check progress. They had the trans out and said the rear main is leaking. Seems like this is getting common. Tigafila

Danno · **Posted:** Fri Jun 22, 2007 9:04 am

Mine had the same oil leak. Turned out to be the valve cover gasket. Oil was just working its way down the back of the engine. They put a die in my oil and told me to drive it for a few days. When I cam back they were able to see where the leak was coming from.

MightyCRD · **Posted:** Mon Jun 25, 2007 11:09 am

I found out that mine is leaking from the rear main seal - it is in the dealer now, and I will be getting it back either Tuesday or Wednesday. I had the "pre-F37" done; my torque converter was leaking from the weld, and they replaced it last October. It's been seeping oil since. If it turns out to NOT be the rear main, I'll post back and advise. It kind of worries me that dropping the pan would cause the seal to go out .... hmmm. Guess we'll see what happens!

Timmaah! · **Posted:** Tue Jun 26, 2007 9:31 pm

After spending most of my life advertising my stupidity is see no reason to stop now. Two weeks and 200 miles after the F37 recall, the engine oil leak has almost completely stopped – no new oil spots on the garage floor. Huh? I finally got around to checking the oil to see how much has leaked out of the engine. The oil level seems to be slightly higher than it was before the Jeep went to the dealership. Did the dealership add some stop-leak to the engine oil? What could that do the good seals in the engine? I have never used the stuff. I hope I am wrong about this.

Timmaah! · **Posted:** Wed Jun 27, 2007 6:23 am

Dammit! My thought process is too slow. I am going to dump this oil immediately and put in fresh oil, just in case stop-leak was added. :oops:

kingofl337 · **Posted:** Thu Jun 28, 2007 2:55 pm

I don't think under any circumstance a dealer would add stop leak to your engine oil. That would be very bad for the turbo amongst other things. It could have just been a loose bolt.

MightyCRD · **Posted:** Thu Jun 28, 2007 2:59 pm

That's odd - I agree that the chances of a dealer adding stopleak would be minimal to nil - but I've been surprised before! Maybe some oil was spilled and has finally finished running off .... ?

I just got mine back Tuesday - mine was a rear-seal leaking. Started leaking after I got the torque converter replaced in October '06. Hopefully now that the rear seal is fixed the TQ won't start leaking again!

Engine Oil Leak After F37

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