Oil leak on a 350!

[bobs409]

A while ago, I installed a different 350 in my truck that I got from a 1975 Impala w/68,000 orig. miles.

I cleaned it all up, put in all new gaskets and painted it. Since I first started using this, it has an oil leak at the rear of the engine. Since everything is clean and freshly painted, I can be 100% certain it's not from the oil pan or coming from the top of the block such as intake, oil pressure switch, etc.

It seems to be coming from the back of the block where the convertor is. The part you can't see when the trans is bolted in.

My question is, is there anything in that area that could leak oil? I believe it's in that area because inside the front of the auto trans behind the convertor is wet with oil. It's puddling up at the bottom where the convertor cover would go.

It's not severe but it's enough to mark it's territory with a dime sized spot of oil after shut down.


Any help would be appreciated.


Bob

 

[yellow wagon]

my 327 drips a little from that area too so I'm curious to see the responses as well

 

[Fathead Racing]

It's fairly common to have a grove worn in the rear seal surface on the crank. New seals will not help. I've heard of welding and turning the crank to fill the grove.

 

[rwagon57]

I agree, its probably leaking from the rear main seal.

 

[No409]

def rear main seal, if your postitve its not the rear lip on the o/p.

i have had lip on the o/p leak, had to tap it up a little bit with a 3/8`s extension and hammer, and it cures leak( this was with a CHEAP oil pan)

 

[jr.W]

If the rear main seal is the problem they make a special seal that moves
the lip in or out to a new spot on the crank. Also check and see if the
dist. is tight.

jr.W

 

[bobs409]

Thanks guys. I'm not so sure it's the rear main because if it was, oil would drip down from there and it would probably be on the back of the pan. Instead, the oil is getting back to the inside of the trans (part that surrounds convertor) and running down in that area.

At first, I did have a pan leak at the rear because the pan that was on here was dented bad. I straightened it out but it must have been distorted so I R&R'd another one and it's dry as a bone all the way around now. Can't be the distributor as the top of the back of engine is also dry.

Wish I had my 4 post lift this year! I'm sick of laying on the ground!

Oh well, I just picked up a "supposed" rebuilt small block yesterday for my other truck so here we go again...


Bob

 

[jr.W]

Bob check to see if the galley plugs or the rear cam plug are leaking. That is if
you can see up between the fly wheel and the block.

 

[bobs409]

Jr, I'll have to see if I can get a look up there with a bright light. There's not much room but maybe... Thanks,


Bob