Since I drove my Explorer off the lot, my engine compartment has been covered with a dirty, oily grime. It's on the engine cover, battery, master cylinder, etc. Even after I clean it, it returns quickly. This is my first turbo vehicle. Is this normal for a turbo motor? Could it be indicative of a boost leak? I'm aware of the blow by associated with turbos, but I'm surprised by the amount of oil outside the system. Would a catch can help?