ok - you dont have to remove the radiator..
Remove the expansion tank bleed screw and expanstion tank locking tabs
Push top of the expansion tank toward engine and lift to free from the lower mounts.
Remove two expansion rivets in the upper corners of the fan shroud. Unclip expansion tank bleed hose located under the shroud.
Remove rubber trip strip between top of shroud and radiator
Using 32mm wrench (BMW special tool 115040) on fan clutch nut. Turn wrench in a clockwise direction working from front of car while counterholding pulley with bmwspecial tool 115030. Spin fan off coolant pump. Note: the radiator cooling fan nut (32mm wrench) has LEFT hand threads.
Unclip AUC sensor from shroud
Lift fan and shroud together out of engine compartment. To replace fan clutch, remove fan mounting bolts and separate viscous clutch from fan. installation is reverse of removal.
Now... I didn't have those "special" tools, I used a combination of a large adjustable wrench and a large flat head screwdriver to keep it in place as I loosened the nut. The nut is SUPER tight and a pain in the arse to get loose without those tools, but it can be done. You cant remove the shroud without removing the fan, they come out together.