So, if I understand correctly, when the car is idling in the driveway, the fan SHOULD be turning and the clutch is engaged under the "low rpm" concept needing more air cause the car is not moving or not moving fast. If the car is moving fast, ie high rpms, the car is typically expected to me traveling fast enough to provide adequate air flow...unless the engine/radiator is still putting off enought heat to engage the clutch, over riding the high rpm clutch cut out. Is this about right?
I was under the belief that the clutch was only temp sensitive and it should let the fan swing free until the engine was hot enough to activate it. i was concerned the clutch was bad when at idle the fan was spinning like crazy.

If all this is correct I see why they changed the design from my 16v with the electro magnetic clutch. The visco clutch is a more simple way get fan at low speed and at hot temps but let is free wheel at low temp and high speeds when it is not needed.
SO if the fan clutch is ok to spin at idle ( the opposite of my 16v) how do I decide if the clutch is good or bad. I figure a bad clutch might be a good reason the fan clutch bracket bearing went bad.

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Christopher Henkel
1990 190E 2.6 - Arctic white SOLD
1986 190E-16v - Blauswartze
1993 300CE - SOLD
2003 W208 CLK 320 Cabriolet - Magma Red