The viscous fan is mounted on the coolant pump shaft. Together with the fan, which has an electric drive, its task is to supply a sufficient amount of air through the radiator.
The fan clutch must be replaced if the hub is scoring and worn. In this case, the fan does not rotate when the engine is stationary or rotates with difficulty. The coupling must also be replaced if the axial or radial clearance exceeds 0.6 mm. To check, it is necessary to move the fan in the longitudinal and transverse directions. In this case, no oil should flow out of the hub.
Withdrawal
1. Remove the intake air guide by removing the clips with a small screwdriver.
2. Unscrew the fan from the coolant pump hub with a 32 mm wrench.
The fastening nut has a left-hand thread and must be rotated to the right to unscrew (arrow illustration).
When loosening the nut, the hub must be kept from rotating with a V-belt. If the nut is particularly tight, you can tap on the wrench with a hammer. The BMW workshop uses a special tool to hold the pulley by the bolt heads. After turning the nut further, it can be twisted by rotating the impeller. Make sure that the impeller does not fall. The fan is removed upwards.
3. Disconnect the impeller from the viscous coupling by removing the screws (arrows in the illustration) and remove the clutch.
Installation
4. Insert the viscous coupling into the impeller and fasten it with screws with a torque of 10 Nm.
5. Fix the fan with the coupling on a nave of the pump of a cooling liquid the moment of 40 Нм. At the same time, hold the hub from turning by the V-belt or the bolt heads.
6. Insert the intake air guide and secure with clips.