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Oil pouring out of ? rear main seal ?
https://slantsix.org/forum/viewtopic.php?t=56693		 Page 1 of 1
Author:  spacecommander [ Sun Dec 07, 2014 5:22 pm ]
Post subject:  Oil pouring out of ? rear main seal ?
Ok, my 19820 W150 truck, the E. Valdez, had a pretty bad oil leak coming from the rear top of the oil pan and from the inspection cover when I bought it a few months back. Had the rear main seal replaced (I would have done it myself but for the filth and mess - hard to deal with given my current living situation). reputable shop, they have done work for me before. They replaced the rear main seal and obviously the pan gasket. No leaks from the pan but oil is everywhere from the engine/bellhousing back, all over the transmission - it's leaking worse now that it was before. About 1/2 quart in 35 miles. Appears like it may actually be spraying out, not dripping. What sort of oil passages and such are under pressure back there that could cause such a bad leak?
Author:  64 Convert [ Mon Dec 08, 2014 3:26 am ]
Post subject: 
A bad oil gauge sending unit will puke out a lot of oil, but it's a little bit forward of where you say.
Author:  nm9stheham [ Mon Dec 08, 2014 6:30 am ]
Post subject: 
There is a plug in the back of the block in the cam bore (cam plug) behind the flywheel/flex plate. If unseated, it would flow oil profusely, as the pressurized oil to the head flows around the rear cam bearing that is immediately behind that plug. Oil from this plug would tend to leak out under the front of the trannie (clutch or torque converter area). Trannie has to come out to get to that.

If that is the issue, then a dished Dorman type plug can be installed once the current plug is removed; clean the plug bore with solvent and use Permatex #1 (Aviation Form-a-Gasket) to seal it.

That same oil to the head flow through a passage in the block and into the head at the back. The head gasket could be leaking there. Oil from here would tend to flow over the top of the bellhousing and trannie.
Author:  spacecommander [ Mon Dec 08, 2014 8:43 am ]
Post subject: 
Cam plug? Hmm. Is there a way to test for leakage there other than yanking the engine? Looks easier to yank the engine rather than the transmission as it's a 4WD with the differential. There is no oil outside the engine, just all pouring down just in front of the inspection plate or so it appears.
Author:  SlantSteve [ Mon Dec 08, 2014 1:22 pm ]
Post subject: 
I think there's only one way to find out ...it's possible they fitted the rubber sump to seal housing rubber seal backwards...the would give you a pretty substantial leak. If they don't seal the bolts for the seal housing I would imagine that's another good possibility.....or the fitted a lip seal backwards....or fitted a new type rope seal...the one I had felt like you were working with a rotted squishy banana ,not a rope seal. If they did the work maybe they should get involved in the issue?
Author:  spacecommander [ Mon Dec 08, 2014 3:05 pm ]
Post subject: 
Quote:
I think there's only one way to find out ...it's possible they fitted the rubber sump to seal housing rubber seal backwards...the would give you a pretty substantial leak. If they don't seal the bolts for the seal housing I would imagine that's another good possibility.....or the fitted a lip seal backwards....or fitted a new type rope seal...the one I had felt like you were working with a rotted squishy banana ,not a rope seal. If they did the work maybe they should get involved in the issue?
Thanks for the tips. I printed out some of the tips and took them and the truck back today. I haven't heard about the rubber sump/seal. Normally I do all my own work but no longer can deal with enormous messes like under car work (brake fluid on epoxy floor = no good) or oil mess everywhere. Wiring, exhaust, cylinder head, etc all ok. Pools of oil or brake fluid = not ok. ;-) This is a very substantial leak . . . and is worse now than before I had it "fixed." They did do a good job on the pan gasket - not a dribble anywhere from that. Split seal, not rope, and yes the owner knew about the offsetting of the seals from the housing halves.
Author:  nm9stheham [ Mon Dec 08, 2014 3:55 pm ]
Post subject: 
Pulling the inspection plate (I presume you mean the lower bellhousing cover.....) and using a mirror might allow you to see up around the cam plug; it will certainly let you see around the other parts of the crank seal area.
Author:  spacecommander [ Mon Dec 08, 2014 4:57 pm ]
Post subject: 
Quote:
Pulling the inspection plate (I presume you mean the lower bellhousing cover.....) and using a mirror might allow you to see up around the cam plug; it will certainly let you see around the other parts of the crank seal area.
That's the plan. He's going to clean everything and see where the oil is coming from. Will mention UV dye if there's any doubt . . . .
Author:  DusterIdiot [ Mon Dec 08, 2014 7:26 pm ]
Post subject:  And/Or...
Quote:
or the fitted a lip seal backwards
Also leaving the crank with original knurling and using the neoprene style seal can wear it away and cause a leak.

Prep in the rear seal area is pretty crucial...if not sealed right even hard acceleration or an uphill drive will leave enough oil against the back of the pan to cause the leak.

If it were the oil galley plug you'd have a couple of scenarios but at higher psi you'd have low oil pressure and lack of oiling at the rockers as most of it was forced out the leak...if it was pretty substantial the idiot light would come on and your engine would complain like it was 4 quarts shy of a full pan in very short order....
Author:  spacecommander [ Mon Dec 08, 2014 9:03 pm ]
Post subject:  Re: And/Or...
Quote:
Quote:
or the fitted a lip seal backwards
Also leaving the crank with original knurling and using the neoprene style seal can wear it away and cause a leak.

Prep in the rear seal area is pretty crucial...if not sealed right even hard acceleration or an uphill drive will leave enough oil against the back of the pan to cause the leak.

If it were the oil galley plug you'd have a couple of scenarios but at higher psi you'd have low oil pressure and lack of oiling at the rockers as most of it was forced out the leak...if it was pretty substantial the idiot light would come on and your engine would complain like it was 4 quarts shy of a full pan in very short order....
Thanks for the info.
Author:  nm9stheham [ Tue Dec 09, 2014 6:23 am ]
Post subject:  Re: And/Or...
Quote:
If it were the oil galley plug you'd have a couple of scenarios but at higher psi you'd have low oil pressure and lack of oiling at the rockers as most of it was forced out the leak...if it was pretty substantial the idiot light would come on and your engine would complain like it was 4 quarts shy of a full pan in very short order....
All depends on how bad that (or any leak) is..... could just be a pin hole leak, or the cam plug...... but looking is going to tell the tale.
Author:  spacecommander [ Tue Dec 09, 2014 12:39 pm ]
Post subject:  Re: And/Or...
Quote:
Quote:
If it were the oil galley plug you'd have a couple of scenarios but at higher psi you'd have low oil pressure and lack of oiling at the rockers as most of it was forced out the leak...if it was pretty substantial the idiot light would come on and your engine would complain like it was 4 quarts shy of a full pan in very short order....
All depends on how bad that (or any leak) is..... could just be a pin hole leak, or the cam plug...... but looking is going to tell the tale.
Lots of oil. Appears to run out more when going up hill. Should hear today or tomorrow. Thanks everybody for the info.
Author:  spacecommander [ Tue Dec 09, 2014 7:17 pm ]
Post subject: 
Hot Dogger! It's back and basically engine oil leak free (well the oil drain plug oozes a few drops). My total hack quickie valve cover repair a few months back has held up, the new head should have the valve guides installed by tomorrow. Shop owner was very honest - said the leak probably wasn't from the rear main seal from the get-go (but they replaced it a second time just in case as they didn't use the centering sleeves the first time) - the oil leak was from the rear of the oil pan. Guess they missed a gasket or got it on wrong or such. If the original gasket had disintegrated maybe they didn't think one was supposed to go there. Now it's just got the manual transmission leak, the transfer case leak and the rear differential leak. ;) Those are terribly minor in comparison. All the rubber in the car is completely baked to death - the window seals for example have to be chipped out of the retaining channels - they are not at all pliable - pulling with needle nosed pliers on any part of the rubber seal just breaks it off. It acts like a ceramic at this point. If the rear gasket on the oil pan was rubber - it probably just fell apart like the door seals and window seals did - most of which was missing.
Author:  nm9stheham [ Wed Dec 10, 2014 6:10 am ]
Post subject: 
That much oil IS 'pretty wrong' for a gasket; glad you got it fixed.
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