How to Install a Water Pump in a 740i

1. Wait for the engine to cool down completely, before proceeding, to avoid burns. Disconnect the negative battery cable by loosening the terminal nut with a wrench. Open the valve on the bottom of the radiator with a wrench and drain the engine coolant into a drain pan. Place the pan out of reach of children and household pets.
2. Note the routing of the serpentine belt by referring to the diagram on the fan shroud. If the diagram is missing, sketch it out on paper. Remove the belt tension by loosening the idler pulley with a wrench then pull the belt away from the engine. Remove the pulley from the water pump by loosening the bolts with a wrench. Remove the three bolts from the thermostat housing with a wrench then remove the thermostat.
3. Remove the bolts from the water pump with a socket and ratchet. Pull the water pump away from the engine block. Clean any remaining gasket material from the engine block with a scraper. Place a new gasket and water pump onto the engine block. Tighten the retaining bolts for the water pump with the socket and ratchet.
4. Install the thermostat and gasket. Tighten the bolts on the thermostat housing with the wrench. Install the water pump pulley and tighten the bolts with the wrench. Route the belt across the pulleys. Add tension to the belt by tightening the idler pulley with the wrench. Proper tension is the ability to depress the belt ¼- to ½-inch on the longest span with your finger.
5. Close the valve on the bottom of the radiator. Replace the engine coolant into the radiator and reservoir. Reconnect the battery terminal and tighten the nut with the wrench. Start the BMW and check for leaks.