03 T6 Massive Oil Leak(s)

thepope540 · Post by **thepope540** » 21 Dec 2019, 11:15

I've read all over the internet trying to find a solution, and I've exhausted everything I can find. I have a 03 XC90 T6 that had an undisclosed oil leak when purchased 3 yrs ago and I've been chasing it ever since. I've rebuilt both turbos (lines and fittings are dry), replaced the entire pcv system, new timing belt (it was due and I was in there checking the cam seals and replacing the oil pump seal), and I've dropped and resealed the oil pan twice.

The car has great compression across all six cylinders, and runs great when driven but can dump as much as a quart in 40 miles. It only seems to leak under load which means it won't leak on the lift. I've tried dye but everything underneath ends up wet so it doesn't really help.

My OBDII scanner shows good vacuum (with auxiliary pump disconnected) under cruise and idle, but the auxiliary vacuum pump runs coninuously when it is plugged in. I get no vacuum at the dipstick tube or oil cap when idling, but there's no pressure either.

I parked it for a year because I was tired of messing with it and now it either needs to be solved or I'm cutting it loose. Any ideas?

Post by **SuperHerman** » 21 Dec 2019, 23:54

Rear Main Seal? Oil dipstick seal (similar to turbo return drain seal).

How many miles? Does the engine have any shake - maybe the crank is wobbling?

Are you saying that if you pull your dipstick or remove your oil cap when the engine is running there is no change in behavior?

A faulty check valve or leaking hose would cause the auxiliary pump to misbehave in the manner you describe.

Backing up - the auxiliary pump and oil leaks were problems before you started working on the car?

thepope540 · Post by **thepope540** » 22 Dec 2019, 06:03

I haven't seen oil at the the bellhousing so I feel pretty good about the rear main.

143k and smooth as silk.

Yes, with the engine running I would expect some change but I get none.

I never noticed the aux pump until I was constantly working on the car. I dont know if I started paying more attention and noticed it or something I did caused it to run more. I bought the car with the oil leak hidden by a towel stuffed above the bell pan. After a couple days we noticed the first oil drips as the towel filled up. I eventually got tired of the mess and started ripping into things.

Post by **SuperHerman** » 22 Dec 2019, 17:49

Throwing darts on the oil leak - oil cooler? It would behave as you mentioned under pressure if the actual hard part, not the sealing rings, has failed.

I suppose for a test you could pull the hose lines, couple them with a pipe, and then end to end the oil cooler with a hose. Then check and see if that solves the problem. Not a long term fix as you are taking the cooler out of the equation.

Basically you are bypassing the cooler with the hose to hose coupler pipe, and sealing the unit with the hose to the inlet and outlet.

thepope540 · Post by **thepope540** » 22 Dec 2019, 17:54

Thanks for the suggestion! I forgot to mention the oil cooler, that was actually one of the first things I replaced.