Water pump (Audi 100 C4)

The coolant circulates in the cooling system thanks to an air pump. The pump can be located on the engine in various places:

On a four-cylinder engine, the pump is located on the front left of the engine in the direction of travel and is driven by a V-belt.
On the five-cylinder and six-cylinder engines, the pump is also located at the front left, but it is driven by a toothed belt. The water pump does not require maintenance during its entire service life. If it leaks or makes unusual sounds, it must be replaced, as the pump cannot be repaired.

Replacing the water pump

Additionally, a new gasket will be required (four-cylinder engine; or a new sealing ring (five-cylinder engine) The water pump, designed for installation on a five-cylinder engine, has the number 5 stamped on the sealing flange and is equipped with a 5 mm diameter sealing ring.

The water pump of a four-cylinder engine consists of the so-called bearing housing (1), in which the impeller of the pump rotates, the thermostat housing or pump housing (3) and the lower cover (2) of the thermostat housing. The arrows indicate the numerous bolts that need to be unscrewed during repair.

The water pump of a four-cylinder engine consists of the so-called bearing housing (1), in which…

On a four-cylinder engine, first remove the V-belt.

Support the car from the front and secure it.

Remove the timing belt cover.

Loosen the seven threaded connections between the front bearing housing and the water pump housing. The pump impeller is located in the bearing housing.

Replace the gasket between the bearing housing and the water pump housing.

If the entire water pump housing is being replaced, the gasket between the housing and the cylinder block must be replaced before installation.

Tighten the bearing housing to a torque of 1 Nm. Tighten the V-belt pulley mounting bolts to a torque of 2 Nm.

On five-cylinder and six-cylinder engines, removing the water pump is done differently:

First remove the servo pump together with the V-belt.

Remove the timing belt cover.

Loosen the timing belt and remove it from the water pump timing belt sprocket.

Remove the rear timing belt cover. To do this, remove the timing belt gear of the camshaft.

Loosen the water pump mounting bolts and remove the pump.

Install the new pump with a new sealing ring. Lightly tighten the bolts.

Install the rear timing belt cover, place the camshaft gear on the shaft so that the protrusion fits into the recess and tighten the mounting bolt to 8 Nm.

Put on the timing belt, adjust the valve timing.

Tighten the timing belt.

Further installation is straightforward. The water pump (1) of the five-cylinder engine is bolted to the cylinder block at the front along with the sealing (3) and running (2) rings.