1. Preparation:
- Park the car on a level surface, apply the parking brake, and turn off the engine.
- Allow the engine to cool down completely to avoid burns.
- Disconnect the negative terminal of the battery to prevent any electrical accidents.
2. Remove the Engine Cooling Fan:
- Locate the engine cooling fan.
- Disconnect the electrical connector to the fan.
- Remove the bolts holding the fan in place and set the fan aside.
3. Remove the Fan Shroud:
- Locate the fan shroud surrounding the fan.
- Remove the bolts holding the shroud in place and remove the shroud.
4. Remove the Drive Belts:
- Locate the drive belts connecting the engine to various components such as the water pump and alternator.
- Loosen the tensioner pulleys to release the tension on the belts.
- Remove the drive belts from the pulleys.
5. Drain the Coolant:
- Locate the drain plug on the bottom of the radiator.
- Place a drain pan beneath the plug.
- Open the drain plug to drain the coolant. Allow the coolant to drain completely.
6. Remove the Thermostat Housing:
- Locate the thermostat housing near the top of the water pump.
- Remove the bolts holding the thermostat housing in place.
- Remove the thermostat housing and gasket.
7. Remove the Water Pump:
- Locate the water pump on the front of the engine.
- Remove the bolts holding the water pump in place.
- Be prepared for residual coolant to come out when removing the water pump.
- Remove the old water pump and clean the mating surface.
8. Install the New Water Pump:
- Transfer the gasket from the old water pump or use a new gasket.
- Place the new water pump into position.
- Secure the water pump with the removed bolts. Tighten the bolts to specification.
9. Reinstall the Thermostat Housing:
- Replace the thermostat housing gasket.
- Position the thermostat housing back in place and secure it with the removed bolts.
10. Reattach the Drive Belts:
- Reinstall the drive belts onto the pulleys.
- Tension the drive belts according to the specified tension.
11. Reinstall the Fan Shroud:
- Position the fan shroud and secure it with the previously removed bolts.
12. Reinstall the Engine Cooling Fan:
- Place the engine cooling fan back into its position.
- Connect the electrical connector to the fan.
- Secure the fan using the removed bolts.
13. Fill with Coolant:
- Mix coolant with water according to the recommended ratio.
- Fill the radiator and expansion tank with the coolant mixture.
- Replace the radiator cap.
14. Bleed the Cooling System:
- Start the engine with the heater set to maximum.
- Let it run for a few minutes with the radiator cap off.
- Squeeze the radiator hoses to help expel air.
- As the coolant level drops from bleeding, continue adding more until the level stays constant.
15. Reconnect the Battery:
- Reconnect the negative terminal of the battery.
16. Test the System:
- Run the engine for a short while.
- Check for any leaks from the water pump area.
- Verify the proper functioning of the cooling system by observing the temperature gauge.
Once you've completed these steps, the water pump on your 1998 BMW 528i should be successfully replaced. Remember, if you are unsure about any of these steps, it is best to consult a qualified mechanic to avoid any complications or damage to your vehicle.
