BMW E46 Water Pump and Thermostat Replacement

Tutorial explaining how to replace the thermostat housing assembly, water pump and coolant drain and fill for an E46 series BMW. The specific video here is a 2002 330xi sedan that had a water pump that was beginning to weep coolant from the main shaft of the water pump. The video shows all the steps necessary to remove all related items on the engine and engine bay to access and properly remove and replace the cooling system components. The BMW parts department advised that I also change the thermostat housing assembly when doing the water pump because an old thermostat could risk failure without a moments notice. The thermostat and water pump and coolant were all purchased directly from BMW. Coolant was mixed using distilled water in a 60/40 solution mixed which I confirmed it's freeze and boiling points using a widely available coolant tester made by Prestone. 1 4 litre jug of coolant or antifreeze (as some call it) can make up to a maximum of 8 litres of coolant mixed at a 50/50 to water ratio. I opted to make a 60/40 because in Canada our climate occasionally CAN dip to 34 degrees Celsius below 0.

It is worth mentioning that doing a water pump replacement on a manual transmission based E46 is easier than one that has an automatic transmission because the cooling fan on the manual transmission 3 series BMWs use an electric cooling fan whereas the automatics use a hydraulically coupled fan clutch assembly that bolts onto the reverse threaded shaft of the water pump. IF you have an automatic transmission E46 then you will NEED to invest in a fan clutch holding tool specific to the E36 and E46 BMWs and a slim profile 32mm wrench to "reverse unscrew" the fan clutch off of the water pump. Not necessarily difficult to do BUT a little more work is involved plus the cost of buying the special tool. Everything else mentioned in this tutorial is otherwise the same.

It is also advisable that since you're removing everything out of the front of the engine that you replace both the serpentine drive belt and the a/c drive belt at the same time.

The motor in my car is a 3.0 inline 6 cylinder M54B30 engine
BMW Parts #'s

11-51-7-527-910 (Water pump) replaces old part # BM11-51-7-503-884
11-53-7-509-227 (Thermostat housing)
83-51-9-415-964 (Engine coolant)