with engine off the fan will be slightly hard to rotate, when you start it up, the fan will roar as it will act engaged because the silicone oil inside pools to one side of the clutch (making it heavy)

once the oil is spread out the fan will freewheel and you can stop it with your fingers easily - it will be quiet and wont instantly speed up with engine rpm either.

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2012 BMW X5 (Beef + Granite suspension model)

1995 E300D - The original humming machine (consumed by Flood 2017)
2000 E320 - The evolution (consumed by flood 2017)