Removal and installation the water pump (VW Passat B4)

To remove, drain the coolant. Remove the generator. Remove the toothed belt protective covers. Loosen the mounting clamps and disconnect the hoses from the water pump. Unscrew the water pump mounting bolts and remove the pump, slightly turning it upwards.

Install the pump on the cylinder block, paying attention to the correct position of the sealing ring. Connect the cooling system hoses to the pump. Fill the cooling system with liquid.

Disassembling and assembling the water pump

Remove the pump drive pulley.

Loosen the bolts securing the pump cover and remove it together with the bushing, shaft and impeller, detach the cover from the gasket plane using light blows of a plastic mallet. Loosen the thermostat nipple and remove the thermostat with the sealing cuff (Fig. 3-23). The pump cover is an integral part of the bearing and cannot be separated from it; if a fault is detected, they are replaced as a set. Install the pump body gasket, having first applied sealant.



Assemble the pump in the reverse order of disassembly.

Replacing the coolant

Remove the expansion tank cap. Disconnect the radiator supply hose from the radiator or water pump and drain the coolant.

Connect the radiator supply hose. Check the reliability of the cooling system hose clamps. Fill the expansion tank with coolant so that its level is between the "min" and "max" marks on the tank. To remove air locks from the cooling system, start the engine and warm it up to normal operating temperature. After the engine has cooled down, check the fluid level in the expansion tank and, if necessary, bring it up to normal.

Checking the tightness of the cooling system

Remove the expansion tank cap and install a hand pump with a pressure gauge instead. Use the hand pump to create excess pressure of 1 kgf/cm² in the system and monitor the pressure on the pressure gauge. The pressure should not decrease. If the pressure decreases, find the leak and restore the tightness of the cooling system.