At idle when warm, The oil pressure should be at least a bar. When driving, right off of idle it should go to the 3bar limit and stay there. When the oil pump or the shaft go, The turbo is the first to dye. These engines are known for oil pump failure. Also I have seen bolts fall into the oil pan from the windage tray and get sucked right through the screen to the oil pump pick up and into the pump. When that happened it killed the pump.
And yep the turbo went south.
ASE CERTIFIED MASTER AUTO TECHNICIAN
LEAD TECHNICIAN FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM