Classic/Antique Car Repair: 58 plymouth 350 big block with a leaky rear main seal, main bearings, mopar engines

Question
Hi Dick  , I have a rebuilt 350 b motor in my 58 Plymouth , its been about a year since the complete rebuild and now the rear mail started to leak while running, is there something I can do with out trying to replace it ? Thanks Tim

Answer
Hi, Tim;

The first thing to do is make sure where the leak really is. Mopar engines are famous for leaking down the back of the block from either a poor sealing valley cover or a leaking oil sender - in either case, it looks like the oil is coming from the rear main seal.

The thing to do is to clean off the whole area back there, start the engine and look to see where the oil is actually coming from - you probably will have to get under the car with a good light to trace it.

If it is indeed coming from the rear main seal, I don't know of anything that will be an easy fix.  I think you will have to drop the pan and loosen the main bearings enough that you can remove and replace the rear main seal.  You could try gooping it up with some Permatex "Ultra Copper", and it might help, but usually the problem is an incorrectly installed rear main seal, and there's no cure that I know of other than to replace it completely.

Good luck!

Dick