Semantics, I would call it an electromagnetic fan clutch but whatever you call it the darn thing should come on earlier. As it turns out when using the A/C the car actually stays cooler as the electric fan will come on with hi side pressure way before the engine gets to 100deg C.
The single pole switch for the fan is usually on the water pump. It is as big around as a quarter, cylindrical and an inch tall with a red top and a single male terminal. I take every one I see and wire the thing straight to ground so that the clutch is always coupled.
I do that since there are no 90 deg C switches; which would make it usefull.
Bosch Master, ASE Master, L1
33 years MB technician