SnapDragon

C-Class Coupe here. This is about the oil in intake issue that this cars have. I have checked a lot of the questions about this issue and have serviced the partial load intake system (valve and nozzles) and cleaned out the high load oil separator without any success. I have been wondering if there are any other factors here. Could oil separator drain be dragging oil back up and into the oil separator down to the catch can? In this document from Mercedes which is attached to this post, they explain that there is a check valve in the drain of the oil separator. On mine there does not seem to be any check valve action going on. Do you guys have such a check valve?


Perhaps a check valve in the circle? Mine doesnt do any check valving action.