Turbo Leaking Oil

[GreenChevelleSS]

My engine had excessive carbon build up in the cylinders and I figured it was the rings so I was thinking of pulling the block and putting in new rings and checking the bearings and all, but today I pulled one of the intake tubes for the intercooler because it was messed up pretty bad what do I find oil pouring out of the intercooler and that tube so I started thinking that it is the turbo causeing all the carbon buildup instead of the rings. What do you think, I highly doubt the turbos ever been rebuilt but the engine is relativily new but who ever built it wasnt very smart. So what do you think should I go ahead and pull the rest of the engine, ive already got the head off, or should I put it back together and rebuild the turbo? Is there a way I can test the turbo for leakage?