My friend has the lifetime powertrian warranty. Major engine issue and dealer says they will put in new engine (refurbished) under warranty. He gets the vehicle back and climbs under only to see an oil leak. It looks to me like the classic rear main seal. I had mine replaced under lifetime powertrain warranty a few years back so Im pretty sure I can spot it. How can the rear main seal be leaking if they just put in a new engine? He brings it back to the dealer and they said its just leftover oil from putting in new engine. They did a dye test and it came back without showing anything. Either the gasket wasnt replaced, was and is incorrect or there is an oil leak from somewhere else? Pics coming from my phone.

 

Pic 1 was after he picked it up. Pick 2 was after he wiped it. Pic 3 was after driving for 20 miles.

 

I would have to agree with them that it is likely leftover oil after replacing the engine. That would happen even after changing the oil pan gasket. Best way to tell is to spray it down with brake cleaner and let dry two or three times and see if oil still shows up after that.

 

If they added dye to the oil I'm assuming it would still be in there. Could a simple specialty light be used to keep an eye on it?

 

update: Since they looked at the vehicle it's bone dry underneath. Even still for it to be leaking that badly to stain my buddies brand new driveway seems to me like sloppy work. Correct me if im wrong on that one but it was a decent amount of oil and my rear main seal didn't leak oil when they replaced it a few years back.