I took the Patrol to a turbo shop a couple of days back because I was leaking oil in the intake, pre-intercooler. This is the same outfit that replaced my turbo in September, so the turbo itself is under warranty. After inspection and disassembly, they were convinced that it was my catch can (Provent 200) leaking oil back into the intake.
Their reasoning was that logically, the heavier oil falls to the bottom of the can and lighter air rises, thus giving the separation that you need, but the outlet (return) for the clean air is on the bottom of the can. After looking at the complete Provent product line, the 200 is the only catch can with this kind of setup - all of their others have inlet and outlet up high on the can.
We also found 3 points on the intake where it wasn't completely sealed, so we fixed those as well, and they were convinced that the combination of dirty air, plus the bad setup on the Provent, were the culprits for the oil leaking into the intake. After doing some quick research on the internet, I found that other have had problems with it as well, but on different vehicles. We "fixed" the Provent - i.e. removed the blow-off valve near the outlet hose and swapped the inlet/outlet hoses.
I was wondering if anyone here has had any problems with their Provent 200 leaking oil into the intake, or do these guys really just not know what they are talking about?