Remove the oil pan. Unbolt the oil pump and lower it from the engine. If the pump is defective, replace it with a new one-don't reuse the original or attempt to rebuild it. Prime the pump by pouring motor oil into the pick-up screen while turning the pump driveshaft. To install the pump, turn the hexagonal driveshaft so it mates with the oil pump drive. Install the pump mounting bolt and tighten it.