“In the bonnet there are channels which connect the line from the crankcase to the valve cover, in addition there is an air admittance valve which when there is too much pressure in the crankcase discharges gases into the intake, and that is why the intake is so dirty in this engine. After removal of the PCV valve unit and directing the gases to the catch tank oil intake is completely clean , well, unless the turbo blows oil..”

source: https://www.facebook.com/groups/365910113441177/permalink/3004654209566741/

“I had the same as a colleague – PVC delete kit and from the crankcase goes to this delete kit, and from there to the cover, and from the cover before the turbo. This way there is no problem with the PVC valve, and some of the oil that went into the intake is caught by the intercoolers.”

source: https://www.facebook.com/groups/365910113441177/permalink/3004654209566741/