Withdrawal
Disconnect the ground wire from the battery.
Loosen the fan shroud. Models 316i since September 1988 and 318i since September 1987: release fan shroud from clips (see section «Removal and installation of a gear belt»).
Unscrew the fan from the water pump hub.
Attention: The nut has a left-hand thread; when unscrewing it, it must be turned to the right.
When loosening the nut, press on the water pump V-belt to keep the hub from turning. If the nut cannot be unscrewed, hit the handle of the wrench on the nut with a hammer.
Remove fan.
If the viscous coupling must be separated from the fan, unscrew the 4 securing bolts -arrows- and remove the coupling.
Installation
Insert the viscous coupling into the fan and tighten the fastening bolts with a tightening torque of 9 Nm.
Attention: To avoid damaging the threads and the coupling, do not overtighten the mounting bolts.
Screw the fan with clutch onto the water pump hub with a tightening torque of 25 Nm. At the same time, keep the hub from turning with a V-belt.
Install fan shroud and secure with screws or clips.
Connect ground wire to battery.