'08 6.4 fully deleted and tuned. Less than a year ago I had whispy bluish white smoke coming out of the exhaust at idle, my mechanic determined it was turbo seals so I want ahead and upgraded to 59/71mm from River City. All well and good aside from non-turbo issues until yesterday. Now I'm back to having the bluish white smoke issue again, although not as bad as last time. Spoke to River City today and the guy said it is at least semi common for the drain tubes to get coked enough to build pressure and push oil past the seals, he also said that if that turns out to be the case the seals are probably fine. It wont be getting looked at for about 2 weeks but im trying to get ahead of the curve (not nearly as smart on this truck as I would like to be) The drain tube thing sounds plausible to me, I have a hard time believing the seals have just quit after less than a year and less than 5,000 miles. Any thoughts on what could be killing my turbo seals? What exactly causes coking, as in is there anything I can do to mitigate it? Obviously to even start figuring this out means cab and turbos off, so $$$. This will be the third time the cab has come off in a year, plus transmission work, I'm trying really hard to find a reason not to sell the truck for whatever i can get and cut my losses but pulling the cab over and over is killing me.