Originally Posted by MR2driver

This is typical for USDM 3SGTE engines. They tend to do that when you run higher boost pressure. You need a catch can to eliminate this problem. You also need to keep it connected to the turbo intake tube, because if you don't, all that oil sludge is going to build up on the top of the head. The turbo intake tube sort of acts as a vacuum to aid in sucking that shit out. There are many theories as to why this happens, but no one knows the actual reason. I beleive it is poor oil circulation in the valve cover.