I have a new 2011 MC and the radiator fan seems very loud to me. I traded in a 2007 MCS that never sounded as loud. I talked to the dealer and they said the sound was normal. I mentioned that the fan came on much more frequently than on the 2007 MCS. The dealer said that the fan is actuated by the A/C condensor temperature as well as the coolant water temperature. The dealer also said that with the A/C on its highest setting the fan will come on regardless of the coolant water temperature.
While I was at the dealership I started another new 2011 MC and turned the A/C on to its maximum cooling. The fan started almost imediately and sounded as loud as on my car. I made another post a few days ago giving the reasons I believe that the radiator fan on the 2011 MC is a single speed. If anyone has a 2011 MC and has heard a lower fan noise please let me know. I am concerned that if my new MINI has a low speed that it is not working.

2011 MC, pepper white, sport seats

 

I also have a 2011 MCS and the fan is loud but it was never anything that really bothered me nor anything I ever considered to be out of the ordinary. I wouldn't worry about it at all.

 

Does it only happen with A/C on?

 

No it also turns on when I'm idle after driving for a bit regardless if the A/C is on or not. Also sometimes stays on after I turn off the car. All examples of normal engine operation in newer vehicles.

 

Yep mine was loud also. I asked about the AC since mine had this crazy loud noise when the AC was on. Turned out after they put on a $1200 A/C compressor and it still was loud they performed the TSB to add a wait to one of the A/C lines....