Oil pan leak on a 1962 Cadillac

[CadillacTom]

I have an oil pan leak on my 1962 Cadillac de Ville. I've changed the gasket twice with no results.
They seem to be some kind of rubber/cardboard gaskets. My mechanic tried all kinds of sealants with
no improvements. It leaks only under pressure while driving, not when the car is shut off. I see
someone is selling Fitzgerald cork gaskets, maybe that will work. Any thoughts from other 1954 to 1962
owners? Thanks, Tom.

[Clewisiii]

Can you clearly see where it is leaking/weeping from.

You have the metal to metal sides but then also the jump over the rear main seal. That is a tricky area to navigate and seal.

[Big Fins]

You say it only leaks under pressure. Is your road draft tube free of obstructions? Oil filler cap the correct type with the breather in it? There shouldn't be any 'pressure' unless you have a seriously worn engine.

If you have a PCV system, is it operating correctly?
Front or rear of the engine? Could be either front cover seal or rear main.

[Michael Petti]

You need to clean the engine bottom with a solvent soaked rag, then start the car maybe on a lift and  then observe exactly where the oil is coming from. 

[Big Fins]

Let me also add oil pressure switch to that list. Sitting on the top rear of the block, they sure can make a royal mess.

[Roger Zimmermann]

Let me also add oil pressure switch to that list. Sitting on the top rear of the block, they sure can make a royal mess.

Exactly! Years ago, just before I wanted to deliver my '56 de Ville, I had a massive oiul leak at the rear of the engine. As it wasw too cold to do the work, I offered as rabate to the buyer and let him do the work. It was "just" the oil pressure switch...which is not easy to replace.

[Big Fins]

Exactly! Years ago, just before I wanted to deliver my '56 de Ville, I had a massive oiul leak at the rear of the engine. As it wasw too cold to do the work, I offered as rabate to the buyer and let him do the work. It was "just" the oil pressure switch...which is not easy to replace.

Maybe not. I have never worked on a '56 in any way.

But a '62 is a walk in the park. It's that special socket that someone made a fortune off of.

[David King (kz78hy)]

Over time, the bolts can be over tightened and slightly deform the area around the holes in the pan.  This will reduce the clamp load of the seal when reinstalled.  Take a straight edge and bridge across the mounting surface of the pan and ensure the are no high spots.  If there are, use a hammer something that fits between the flange and valley and tap the holes back flat.