The coolant pump must be replaced in the following order: Remove the alternator drive belt, drain the coolant and send it for disposal.
Remove the radiator, fan impeller with viscous coupling, torsional vibration damper, thermostat housing, pulley from the coolant pump hub, and cooling system hoses.
Mark the coolant pump mounting bolts, unscrew them and remove the pump.
When installing the pump, clean the sealing surfaces and replace the sealing gasket. Make sure that the centering bushings are positioned correctly (arrows, Fig. 4.106).
Tighten the thermostat housing mounting bolts (M6) to a torque of 10 N·m (1.0 kgf·m). Tighten the four pulley mounting bolts (M6) to a torque of 10 N·m (1.0 kgf·m). Install the drain plug (M14x1.5), replacing the sealing ring, and tighten it to a torque of 25 N·m (2.5 kgf·m).
Fill the system with coolant, bleed the system, start the engine, warm it up and check the system for leaks. Check the coolant level and restore it if necessary.
(The article text was copied from an online resource «bmwman.ru»)