Oil leak from Pan ONLY when running
 

There is a cotter pin coming out of the very rear bottom of the oil pan that is bent so that it will not exit the hole but it does spin like a propeller. Had the oil changed today on a lift and my mechanic said it was dripping oil from that hole only when it was running. It is a 39 Ford Deluxe Convertible. The motor has been changed to a 59AB with oil filter.



Any and all ideas as to what this cotter pin does and if there is a quick fix to the oil leak will be appreciated. Thanks in advance.

Re: Oil leak from Pan ONLY when running
 

That's not your oil pan, it's your clutch housing. The cotter pin is there to prevent that hole from clogging up. Oil is expected to exit there to keep it off the clutch. Your "mechanic" has apparently overfilled the crankcase, thus allowing the excess oil to dump out the rear seal to the clutch housing. You need a new mechanic or preferably, do it yourself so you know it's done right.

Re: Oil leak from Pan ONLY when running
 

And what weight oil did he use ? Did he do any other work ? Change vacuum lines, PCV , (if applicable) ?

Re: Oil leak from Pan ONLY when running
 

Recently assembled? Oil pump drive gear cover......

Re: Oil leak from Pan ONLY when running
 

The late great Bruce Lancaster said the cotter pin is there to keep the leaking oil from getting gummed up and clogging the hole. The oil is there to keep the cotter pin from rusting.