The crank case from the factory is vented into the intake right before the turbo. This puts oil in the charge air system. Your intercooler boots will become saturated with oil if they aren't already and really makes the intake manifold on EGR equipped trucks extremely nasty. There are three ways to fix this. 1) Run the crankcase vapors through a filter, then direct it back into the original location in the intake. 2) Just plug the spot in the intake and vent the crank case to the atmoshpere. 3) Plug the port on the intake and run it to your exhaust and let it dump there.