Proper operation of cooling fan? ('92 190E 2.3)
 

What is the proper operating sequence of the cooling fan on a M102 190E? Currently, the car's normal operating temp is around 80, the electric fan kicks in at around 90 (or is it 95). I think that is normal. However, the mechanical fan seems to always on. At 5000-6000 RPM I can still hear the fan turning. I thought the clutch was supposed to disengage it above a certain RPM since you have good airflow to the rad when the car moves. Sometimes I open the hood with the engine running and I can see the fan turning a little slower. Is everything normal?