Oil Leak

[farm1810]

Greetings all.  I have a pretty bad oil leak out the rear of the engine, only when it is running.  It will dump a basketball size puddle in about 10 minutes.  I used the UV solution in the engine oil just to be sure it is engine oil (didn't smell like gear oil anyway, but just wanted to be sure).  I have purchased the needed parts and tool to replace the rear main seal (I already replaced the pan gasket hoping that was it).  In looking at the service manual it talks about not starting the timing gear with a mallet as the cam can move rearward and dislodge the plug in the block at the rear of the cam bore and oil leakage can result from this.  I did replace the timing gear a short time ago and did start the gear with a rubber mallet.  How likely is it that I have dislodged that plug and that is the oil leak?  Thanks. 

[Rus Curtis]

Since that end plug is up higher on the block, IF it were leaking, I'd assume you'd see it when looking at the back of the engine (up against the fire wall) and over the top/down the sides of the bell housing.  Inserting anything that will fit between the block and the firewall that could be used as a "wipe" will help confirm that plug is dry or wet.

Had to look for a light colored engine so that the plug would be easier to see vs. a black engine (F-head but cam plug should be the same on L-head):

https://cj3b.info/Photos/Owners/1959/McIntyre59/McIntyreEngineRear.jpg

If the oil is coming out of the weep hole at the bottom of the bell housing or only seen between the oil pan and bell housing, it may more likely be the rear seal.

Consulting Murphy, it may be both......

[Chuck W.]

Rus, not sure you are looking at the correct plug, the cam plug is lower down and inside the bellhousing, so any oil would leak out the bottom of the bell housing and might look like a rear main leaking. However, if he had knocked the plug loose, I think it would leak a tremendous amount of oil


(photo from Willys M Jeeps page)

[Rus Curtis]

Spot on!  I was looking at that freeze plug!

Good catch!

[OlDaz]

Did it start leaking like that as soon as you started it up after the work you did on it? Or was it OK for a while, then just started doing it?? Either way you're going to have to investigate by either pulling the engine or the trans. Personally I would pull the engine as I find that easier. I know that with a bit of messing around you can replace the rope type seal without pulling either, but IMHO I would pull the engine, then the flywheel so you can either eliminate or prove the cam plug is the culprit. If it's not, then you are halfway into it to replace the rear main seal and you'll get the peace of mind that you have eliminated one possibility.

[Rus Curtis]

I like this approach.  I've read about owners replacing the seal from under the jeep.  I like the idea of having everything out of the way to give me the best chance of a good install.

And the inspection will verify where the leak is actually coming from.