Linda (Plymouth, New Hampshire)
They lost the oil cap and they can hear it rattling around in the engine whenever they start the truck up or go around a corner. But, they can't find it! Do they have a problem? It might be stuck behind the water pump pulley. Eventually it will fall out, or get ground up. Worst case, it will flip off the serpentine belt. Take off the serpentine belt, spin everything, and listen for the sound of the oil cap.