I noticed the dreaded smell of burning oil this morning after cranking up the slk. Upon inspection, the oil seems to be seeping from a black round plastic cap that is to the left of the oil dip stick. The fact that it is dripping down to the catalytic converter scares me as it could be a fire hazard. Can someone please confirm that the part I'm looking at is the cam expansion plug? This is on the passenger side, 06 slk280.