Oil Leak Question
 

Sorry, I know this has been hashed over again and again, but I'm learning, researching.....and I found this old post:
'Model A rear main leaks seldom leak while the engine is running. They "mark their spots" when the engine is stopped.'
This got me to thinking.....mine leaks from the cotter key while running, driving, stopped, idling and for a while after it's shut off. Any possibility that it's not a rear main issue? I'm about to drop the oil pan and just want to make sure I'm not making more work for myself if I don't need to.

Re: Oil Leak Question
 

If it is leaking from the flywheel housing drain hole, that means it is leaking from the back of the block to the flywheel housing. Some people use a gasket there, others use rtv. There are two bolt holes that it can leak from and also around the camshaft hole. To fix this you would have to pull the engine of course!

Re: Oil Leak Question
 

Any way to tell the difference before the engine is out?

Re: Oil Leak Question
 

Since the flywheel housing drain hole and cotter pin is the lowest spot from the front part of the engine, an oil leak anywhere further forward on the engine can run back and appear to drain from that location. Check other likely places for oil leaks - valve chamber cover, oil return tube and rear oil pan bolts. The 4 rear-most oil pan bolt holes open into the crankcase and should be sealed with RTV or other sealer when they are installed.

The rear oil pan gasket - the cork strip that fits around the lower rear main bearing cap - can also leak.

Checking these other locations may save you some work.

All Model A engines will leak a drop or two from the rear part of the engine. If you’re seeing more oil than this, check for leaks elsewhere before dropping the pan.

Good luck.
Jim

Re: Oil Leak Question
 

Yeah, I have a puddle and a nice trail to find my way home!

Re: Oil Leak Question
 

Did the oil leak come spontaniously, gradually, after rebuilding or what ?

Henk

Re: Oil Leak Question
 

Unfortunately I bought it this way. Just couldn't turn my first Model A up! lol It's a long story, but the original owner rebuilt the engine about 10 years and 1,000 miles ago. He said it used to leak with him and he just ran it two quarts short. Oh, boy. I wonder about things like.....proper dip stick.....major sludge in the pan.....?

Re: Oil Leak Question
 

You might get some idea of the source if you remove the flywheel housing cover behind the pan. Clean and dry everything you can get to. The bottom of the main cap is accessible. Dry it, the pan, the gaskets, everything. Start the car and run until it drips. Then crawl back underneath with a flashlight. With some luck you might see a source; of leak other that the bearing. Worth a try before tearing into it.

Re: Oil Leak Question
 

I feel your pain.

I have the same issue. Take her out for a run.....bring it back home into the garage and a nice trail of oil on the garage floor then it drips a nice puddle on the cardboard once parked.

I have torn this engine out 3 times in an attempt to fix this issue.

At first it was running down the outside of the flywheel housing from the main area.
Now it is dripping from the bottom hole in the housing.

1. Leaking form the rear cam hole as there was no gasket.
2. Next leaking from the rear main. I had a hole in the babbit. Plugged that. Didn't solve the issue.
3. Replaced all the babbit (it was a bad babbit job) with insert bearings, mains and rods. For the first few outings no leaks then the trail begins! :(
4. Now, I will attempt to see what is going on to cause this.

Gets a little frustrating after awhile!

Looking up from the bottom to the rear main area it is dry so I am hoping it is not the rear main.
We RTV'd the cam hole gasket so pretty sure it's not from that.
Did likewise to the rear cork pan gasket.
So drain tube?
We made sure everything was clear in the passage ways and the tube.
Valve cover is dry.
A little weeping at the top oil return pipe but not enough to cause this much oil flow besides it would drip on the ground from there not through the hole in the flywheel housing.

I'll pull the flywheel housing cover off, dry everything in that area and run it to see if I can see where it is coming from.

Re: Oil Leak Question
 

Does anyone sell re-babbitted rear main bearing caps?

Re: Oil Leak Question
 

I have used Fluorescent Dye and an ultraviolet light to trace leaks in the past. You might give it a try to help locate your source. It works best when it is dark out.

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Re: Oil Leak Question
 

^^^^^
There's a thought......Thanks

Re: Oil Leak Question
 

CatMan1 QUOTE: Any way to tell the difference before the engine is out?

With the pan off, I have used an oil filled 20ml syringe with a tapered fitting pressed into the rear main oil port at the back end of the valve chamber. Push in the oil slowly to simulate the normal low pressure and watch where it goes. I found a lot coming out around the two bolts so I wrapped both ends just below the bolt top and above the bottom nut with linen fishing line, dobbed on some non hardening Permatex Aviation sealant, and and replaced them in the block. The combination of linen line and Permatex stopped any oil from leaking at that point.

Re: Oil Leak Question
 

A lesser possibility is trans oil getting past the forward bearing or oil being pumped out by the shift rails. These problems are usually serviced by a shielded bearing and a shift rail plug adapter. A leakless Model A is something of an illusive dream - but your case seems excessive. Please share the cure when the caper is solved.