Substantial oil leak aft of oil pan

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Scooter7
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Substantial oil leak aft of oil pan

Post by Scooter7 »

After running to the store and returning home I noticed a substantial oil leak aft of the oil pan out of this hole. It appears to me that this hole allows oil to exit the housing, indicating a seal of some sort has gone bad inside. It leaked from the hole at about one drip every other second for about 20 minutes, creating a nice oil slick. Also dripped slowly from the housing bolt right next to it. Not sure where to start with this one and curious if anyone has previous experience with this. Thanks in advance.
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Hotzenplotz
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Re: Substantial oil leak aft of oil pan

Post by Hotzenplotz »

Scooter7

Apparently you have oil dripping out of the bellhouse. Can be from two sides: engine or gearbox.
Take out the gearbox and look for the culprit. As far as I can tell on the pics it looks like the crankshaft seal is leaking, can also be the seal on the gear housing behind.
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pcolette
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Re: Substantial oil leak aft of oil pan

Post by pcolette »

I had a leak that looked like this once. Turned out the seals between the oil cooler and its mounting point were leaking and running down the side of the engine, then dripping at the lowest point. Not a hard job to replace and the seals and gasket needed are under $10.

If it is actually coming out of the bell housing then it's possible the rear main seal has failed.
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whitesik
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Re: Substantial oil leak aft of oil pan

Post by whitesik »

Similarly, I had a leaking fuel pump gasket that also dripped to the same location. Another easy fix. I hope yours sources back to something easy.
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Scooter7
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Re: Substantial oil leak aft of oil pan

Post by Scooter7 »

Thanks all for the heads up. I'll have to dig into it after a work trip and I'll be sure to advise on my findings, as I know i'll need guidance from there. Much Appreciated
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rmel
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Re: Substantial oil leak aft of oil pan

Post by rmel »

It also appears from the PIX you have a fair amount of oil leaking down the side
of the engine, which may be another clue the leak is associated with the Oil cooler
or fuel pump. One thing to try is to remove the Tranie access cover inside the
truck, then remove the small bell housing cover which would then expose the starter
drive gear and the flywheel. Look to see if the flywheel is wet with oil. I had a leak
just recently that turned out to be along the seam of the cam gear housing, was
small enough that a good application of RTV fixed that. When I pulled these access
covers it was very evifent that the flywheel and inside of the bell housing was dry.
Puller: 71' 710K 2.7L EFI aka Mozo
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Jimm391730
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Re: Substantial oil leak aft of oil pan

Post by Jimm391730 »

Another clue would be that gear oil can have a smell that is distinctively different than motor oil. See if you can smell the difference, and apply that to what is dripping. But based on the color, I would expect that you are seeing motor oil. With the wind buffeting around the leak could be almost anywhere.

Another method would be to pressure wash the oil off everything down below, then start the engine idling for 20 minutes and see what drips and from where without any wind blowing it around.
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boeing7873
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Re: Substantial oil leak aft of oil pan

Post by boeing7873 »

I bet oil cooler. I see too much oil on the right side.
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rmel
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Re: Substantial oil leak aft of oil pan

Post by rmel »

The procedure I find that works fairly well is to thoroughly clean all surfaces -- muck obscures the source.
I have also found that a high resolution LED borescope tends to accentuate the visibility of oil showing a "deep yellow".
https://www.amazon.com/gp/product/B01MY ... UTF8&psc=1

Run the truck at idle -- occasionally looking at areas of interest, if it's a leak under pressure e.g. the mounting point
to the engine block of the Oil cooler you should see some tell tale signs. Or the mounting point of the cooler to the Oil
Filter housing. Also look around the base of the starter for any signs of a Cam housing seam leak. If it's the rear main
seal, should see most of the leaking out of the bottom hole of the Bell housing.

From the PIX's I'd be more apt to suspect the Oil cooler.

Funny, I hate plumbing, fix one thing and you break another. I fixed a Cam housing seam leak, but to fix that you have to
remove the starter and it's mount, to get to that you need to remove the dip-stick which bolts to one of the Oil cooler
mounting bolts. Well removing that one nut was enough to break the seal and a new leak developed :( All fixed now. But if
you need to remove the Oil cooler assembly IMHO also replace the inner seals on the cooler to Filter housing. When
I pulled these two rubber seals they were very hard and getting brittle.
Puller: 71' 710K 2.7L EFI aka Mozo
Follower: Sankey MK 3, 3/4 Tonne
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kdiqq
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Re: Substantial oil leak aft of oil pan

Post by kdiqq »

How often to rear main seals fail? I have a similar, though less severe leak and I've already replaced the oil cooler gasket and fuel pump gasket.

Image

SAV is showing a gasket that goes between the engine and timing set cover and that looks like a pain to do compared to the RMS. I figure if I'm pulling a tranny though, it's worth doing both..
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boeing7873
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Re: Substantial oil leak aft of oil pan

Post by boeing7873 »

You mentioned oil cooler gasket, is that 31. I can think of these places before you go into the difficult stuff:
Items:
6
28
29
31
33
My mess was from the rubber seals (33) between the cooler and the thermostat body. They were rock solid.
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Re: Substantial oil leak aft of oil pan

Post by boeing7873 »

How in hell do you post a picture like you did kdiqq?
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Hotzenplotz
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Re: Substantial oil leak aft of oil pan

Post by Hotzenplotz »

boeing7873 wrote:How in hell do you post a picture like you did kdiqq?
Well you can either take a screenshot of SAV (as he did) or link directly to the site .
Surf to SAV, right click to the pic and select "save image path" then enter it here like
square bracket left img]http://www.pinzgauer.com/img/assemblies/01-15.png[/imgsquare bracket right

I had to verbalize the [ and ] brackets to avoid inserting the real pic like

Image
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kdiqq
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Re: Substantial oil leak aft of oil pan

Post by kdiqq »

boeing7873 wrote:How in hell do you post a picture like you did kdiqq?
You have to be a seasoned professional.

Or do what was said above. I used SAV diagrams. If they are missing something, usually the service manual can fill the gap.

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edzz
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Re: Substantial oil leak aft of oil pan

Post by edzz »

May want to take a good look at your mounts while your down there.
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