L-134 oil leak

jsnwalker · Post by **jsnwalker** » Wed May 10, 2017 9:27 pm

Hey guys, just finished installing the power plant into my '52 M38 after doing some work on the tranny and transfer case. The engine itself is in really good shape except for the oil pan gasket which I replaced. Everything above oil pan is oil free and 'clean' while the oil pan was filthy. I pulled it off, cleaned it up, put on a new gasket and bolted it back up. Turns out I still have two sizeable oil leaks. Since this is my first go at a motor fix up, I'm a little stumped as to what could be the cause and wanted to know what you guys think.

The first leak is dripping from where the bell housing bolts up to the thin mounting plate between motor and bell housing. Since I just rebuilt the tranny myself and am familiar with the flywheel back, it seems like the leak is coming from behind the fly wheel. From the manuals and exploded view photos I have seem, it seems like the only real possibility is the rear main oil seal?

The second leak is dripping off a point of the oil pan skid plate directly below the oil pan drain bolt. I checked the bolt and seal while I was installing the oil pan and everything looked great and I made sure it was nice and snug. Also, the oil pan itself directly below the drain seems dry as if no oil was coming from there but the space between the skid plate and pan is crazy oily. While cleaning the oil pan before installing the new gaskets, I didn't notice any damage or holes to cause a leak. My worry is that there is a hole (maybe a small burn hole from the welding the skid plate?) between the skid plate and bottom of the pan causing the leak. Anyone run into that issue before? Again, everything above the oil pan is free of oil.

4x4M38 · Post by **4x4M38** » Thu May 11, 2017 5:56 am

Walker,
There are two possible locations for an engine leak at the rear.
The rear main seal as you noted, and the cam welsh plug.
It is similar to a freeze plug and can be readily removed and
replaced, if the flywheel is off!!

Pan leak. Oil, like water, can wander for a ways from its source.
You might have a pinhole, or possibly a weld as you suggested,
rusting or cracked due to snagging the plate on something.

Have you completely eliminated the gasket area? Over time the bolts
holding the pan on get tightened more and more, which deforms the pan
at those areas at the bolt holes. Those deformities create sealing problems
between the block and pan.

Suggest you remove the pan and clean it thoroughly. Inspect it closely
inside and out, and ensure the sealing area is nice and flat. If that doesn't
identify the culprit Bretto suggested floating the pan in water with the plug in,
pushing down enough to try and get water everywhere under the bottom
and sides without it spilling into the pan.

If you have a leak it will show up.

RickG used his bathtub, but I don't think I can get away with that!

Take care,

keats · Post by **keats** » Thu May 11, 2017 8:50 am

Use a bright flashlight. Place the pan over the light and turn off the lights. The flashlight beam will show where the leak is.

45auto · Post by **45auto** » Thu May 11, 2017 12:34 pm

If you are new to these old jeeps you will find over time the problems we are having they did not have when they were much newer. Time is its worst enemy!!

If the oil leak at the rear of the engine is more of a dip, most likely its the rear main seal. There have been problems with the new rubber seals---you can google Willys Rear Main Seals and see what you need to be on the look out for if you decide to tackle replacing it.

The oil pan leak sounds like there is a pin hole in the bottom of the pan. If the oil pan had a layer of thick sludge on the bottom when you last had it off, it was from the lack of oil changes which contains acid that normally burns off when running the engine at operating temperature. Short runs, stuck thermostats and few if any oil changes results in the layer of sludge you found in the oil pan. As it sits for years the acid slowly eats away at the medal.

What you are looking for is what looks like a "black flake" on the bottom of the oil pan. Dig at it with a pick and most likely its a hole. Use a cleaner that will remove the oil and seal it with a sealer that will harden up. I use JB weld however, other sealers will work. You just want it to be oil and heat resistant and get it down into the hole and feather it out on top.

Next, since you have the oil pan off, check the surface of the mounting flange to see if the oil pan bolt holes are dimple inward. if they are, use a bolt the same size as the hole along with two flat washers, one on top and bottom, and tighten the bolt and it will pull the dimple back straight and level. Although not original, use bolts with a flange head or use flat washers to spread the torque and resist cranking down on them. A 1/4 inch drive ratchet works good and keeps you from over tightening the bolts.

Let us know what you find!!

4x4M38 · Post by **4x4M38** » Thu May 11, 2017 3:43 pm

Wow that washer trick is slick, Harold!

Post by **wesk** » Thu May 11, 2017 8:18 pm

I just insert a 2 foot 2x4 long skinny edge up in the vise. Lay the pan mating surface on the top edge of the 2x4 open side up. Have a buddy hold the pan tightly against the 2x4 and level while you grab TWO ballpean hammers. You lay the ball of one ballpean hammer into the upward dimpled hole. Then you sack the flat side of that Ballpean with your second ballpean hammer.

jsnwalker · Post by **jsnwalker** » Fri May 12, 2017 9:00 am

Thanks for the tips everyone. There was a TON of sludge in the bottom of the pan that I scraped/scrubbed clean before reassembly. I also flattened out the mating surface using a hammer and a scrape piece of metal. I was happy with the result when done and it seems to have done the trick.

Both leaks are drips but the rear leak drips more often. The first time I was able to test drive this baby I rode up and down my street, less than a 1/4 mile and then parked it for the night. In the morning, both had puddles between 4-6" diameter underneath. No bueno.

Looks like I'm going to have to pull the motor after all! I'll rip into it this weekend and see what I can find under there but sounds like I should replace the rear main seal and cam plug at the same time since I'm right there.

Post by **wesk** » Fri May 12, 2017 9:03 am

Unless you are overhauling the engine or when you remove the flywheel you see a wet stream of oil leaving the rear cam bore plug leave it alone.

The rear seal can be fussy but so can the junction of the oil pan gasket and the rear main cap!

jsnwalker · Post by **jsnwalker** » Fri May 12, 2017 9:08 am

'If it isn't broke, don't fix it'. Fair enough. I hope it is as easy as 'follow the oil trail' to the problem area. Let the fun begin!

jsnwalker · Post by **jsnwalker** » Mon May 22, 2017 9:25 am

I got the motor pulled out and resting safely on an engine stand. I felt a little relieved when I saw what I was dealing with; the welsh plug is nice and clean and everything looks relatively clean. I didn't see an 'oil trail' coming from the rear main seal however but from what you guys said, it can only be coming from the plug, rear seal or oil pan so I still feel confident its the rear seal that is bad? And I can't really imagine that a leak from the oil pan flange would seep up into this area?

Post by **wesk** » Mon May 22, 2017 9:54 am

Post a photo of the other side of that adapter plate in your 1st photo.

jsnwalker · Post by **jsnwalker** » Mon May 22, 2017 1:15 pm

Here is the other side of the plate.

For the comments in the photos you posted:

- I did add some sealer to the oil pan when putting it together and yes, that photo does make it look like I used half a tube. I bolted on the oil pan while laying on my back under the motor so everything was sliding around and making it look horrible. Should have wiped it up when I was done bolting it on...

- For the adapter plate gaskets, you mean there should be a gasket between the motor and plate AND between the plate and bell housing? I didn't notice any gasket remains while pulling this apart.

- It seems like your leaning towards the tube seals and oil pan being the culprit. In order to change the tube seals, I am basically replacing the rear mail seal since I have to remove the crankshaft?

jsnwalker · Post by **jsnwalker** » Mon May 22, 2017 5:54 pm

alright, now that the motor is on the stand and I handed everything cleaned up, I see the two holes where the tube seals go and there was nothing in either of them. While looking at the install instructions, I read that you needed to pull the crankshaft and end cap in order to replace both the tube seals and main seal but the tube seals I have just drop in place with a little room to move around. I assume when the oil pan is booked down, it smashes the tube seals causing them to expand and fill the void? Do I truly need to pull the crank shaft to install these seals? That would be a nice end to a Monday if I didn't have to!

Post by **wesk** » Mon May 22, 2017 10:07 pm

The tube seals are a fixed length longer (about 1/4") than the hole so the compression by the pan expands them to a tight fit. When you removed the pan the last time they may have permanently shrunk in length and did not offer enough compression to reseal.

Be sure to review my Rear Oil Seal Photo album: http://www.willysmjeeps.com/v2/modules. ... _album.php

It can be a tough call on just how much to do now. The key to your decision is how much you enjoyed this last exercise in removing the engine and weather or not you are willing to do it again in the very near future.

My choice this far into things is to remove the pane and the crank. Thoroughly inspect the bearings, crank, seal surfaces. If the crank has a rope type seal it's time to decide if you want to switch to a preformed seal. If you make the switch you must be positive the crank is machined correctly for the preformed seal and check the dimensions.

This is the dimension check.

This is a bad sealing surface.

This is a proper sealing surface.

At this point the decisions become tougher because you are only 6 hours away from a complete overhaul!

jsnwalker · Post by **jsnwalker** » Mon May 22, 2017 11:16 pm

Ha, I learned that your '45 minutes to remove a motor' really meant 3.5 hours for me so an additional 6 hours of work is more like 2 solid weeks for me! I think i will have to gamble with the crank shaft and rear seal as is this go around. My wife is going to murder me if she sees me spend more on this jeep for a while... happy wife, happy life as they say.

Since I'm going the risky route, are those tube seals as easy as stick in the hole and bolt the oil pan down? Do you recommend any type of sealer or coating of oil to make sure it compacts properly?