As the subject says, my 535i is:

- running cooler than ever before (if the temp gauge goes from 10-2 o'clock it's running at about 11)
- making noise that increases with increasing engine rpm
- having a distinct loss of power when the noise is present

Also, I can actually see the fan turn faster when I'm revving the engine in neutral.

Am I correct in guessing that the fan clutch needs replacing?