My M35 has recently developed an issue where oil residue is accumulating at the bottom of the pipe that goes from the intercooler up to the inlet manifold and when you stop a strong smell of oil comes in the cabin. I've pulled the intercooler and associated pipes off and cleaned inside them and checked all hose fittings the only one that i have not removed is the plastic pipe that runs up to the the manifold as it's difficult to get at the securing bolt without dismantling half the car. Could that pipe be split or does anybody have any other suggestions, the car has done 168.000 klms and has lost no performance.