Water pump for BMW «518», «520» cars (BMW 5 Series E12)

Removal the water pump

Disconnect the wire from the negative terminal of the battery.

Unscrew the radiator filler plug and open the interior heater valve by setting the switch handle to the "warm" position. Place a container under the engine to drain the fluid, disconnect the drain hose from the radiator, unscrew the drain plug located at the rear of the cylinder block on the right, and drain the fluid.

Remove the radiator and fan.

Loosen and remove the alternator drive belt.

Disconnect the inlet and outlet hoses from the water pump and remove the water pump.

Disassembly and assembly of the water pump

Press off the pump drive pulley with a universal double-lever puller.

Remove the retaining ring and press the impeller and bearing off the shaft using a press.

Press together the cuff 2 (see photo) and the thrust sealing ring 3.



Wash the parts and check their technical condition. The water pump is assembled in the reverse order of removal, taking into account the following:

• press the impeller onto the roller, applying a sealant such as Loctite AVV to the mating surfaces. In this case, it is necessary to maintain the dimension "B" of 1±0.2 mm, shown in the photo. When installing previously used parts, apply a pressing force of approximately 400 kgf, and for new parts it should be equal to 500 kgf;
• when installing the hub, maintain dimension "A" 91.8±0.2 mm, shown in the photo.

Installing a water pump

Clean the mating surfaces thoroughly and replace the copper washers.

Further installation of the water pump is performed in the reverse order of removal. Fill with coolant, having first turned the heater control valve switch handle clockwise until it stops.

Start the engine and check for coolant leaks.

(Read the original source on the website «BMWMan»)