you and I appreciate any help in advance.

So, form the beginning...I purchased a 2001 A6 2.7T in a mechanical condition other than great. The car ran upon obtaining it...barely. It ran rough. The original symptoms were, running rough (missing), and tons of oil and smoke out of the exhaust. Any oil that you would put in the engine would promptly end up in the exhaust and intake system.

So, obviously it wasn't a normal wear item like valve seals or something like that.

My first thoughts were a head or block issue, because I noticed oil in the coolant as well...but no coolant in the oil. But lately I've moved to a new theory. Since the turbos in this setup are cooled/lubed by oil AND coolant, I figured the turbo seals probably blew and it is allowing A LOT of oil into the exhaust and also causing some mixing between the two systems.

I have pulled the engine, but before I did, I did a compression test on all cylinders and they all checked out good. (That's another reason I was doubting a head/gasket issue. When I did briefly run the engine there was also no obvious knock or anything, so I think the block should be okay.

So, after pulling the engine, I removed the first turbo and it does have excess play in both direction (both in and out and side to side) so I know those turbos are pretty much done. The one thing I'm stumped on right now is diagnosing the root problem for sure.

I was trying to prove that there is in fact a massive leak from the oil in the bearings of the turbo to the exhaust side and probably even the intake side. The only test I've done so far is to plug the input hole of the exhaust side of the turbo with it sitting up on end (waste-gate and exhaust exit side up) and fill that end with some water. Then, plug one the the oil line ports and pressurize the other port with compressed air. My thoughts were that if there was a bad bearing oil leak that I would get bubbles in the water...and I did. So I thought I had nailed down the source of the issue. BUT...

I had picked up some very reasonably priced used "good" turbos on eBay just recently and had them on hand so I figured why not run that same "test" on them as well. So, I set them up the same way and pressurized the bearing area..aaannndd BUBBLES!!

So, in conclusion, I either purchased a bad set of used turbos on eBay that have the same problem as the ones on the broken engine, or my made up "test" is flawed because I don't totally understand the makeup of the internals of these turbos and there is another issue in the motor.

Sorry for the long post, what I'm really asking is...does anyone know if getting pressurized air passing from the oil section of the K03 to the exhaust side is normal?

Thanks

 

Maybe not much help but I see no other responses. I had an oil/water non Audi turbo with a plugged oil return line once. Gobs of smoke out the tailpipe and no mosquitos in my area for a while. It was quite a long timee ago but I don't remember it running rough, just a LOT of smoke on acceleration. I took care of it almost right away so I don't know about coolant and oil mixing. Don't know about bubbles either. I would think the pressure build up from a plugged oil return line could cause oil to get into the coolant.