Ok....there is definitely an rpm dependent whine present, which rises an falls in pitch throughout the rpm scale, but ONLY when the A/C is on, (compressor) is engaged. It is present no matter if I'm in or out of dynamic or sport mode. The A/C is blowing good cold air even with 100 degree plus temps outside. Could it be the compressor itself? Is this normal? It certainly is Not a metallic or grinding whine. Has anyone experienced this? I Don't imagine one would hear it with the music up or air blowing loudly in ones ear, but to me, it's a bit more than subtle. If I accelerate through the gears with A/C on an then off, I can really hear the difference. Anyone else?
Thanks
CRS

 

Is the noise coming from the engine bay or from behind the dashboard?

I do not have similar issues on my car. It has a similar sounds AC on or not...

As you know AC motor is using engine power to cool the air down so there might be some issue with the compressor itself.

 

Coming from engine bay. Definitely compressor related in that the noise appears when I engage the compressor, and immediately disappears when I turn the compressor off. The whine (and it is slight, not super loud) has a slightly different pitch, so it's easy to discern, and the pitch rises and falls with acceleration. Hmmmm......
CRS

 

Did you diagnose what the issue was?

 

Not yet. When I take the car in for its first service, it will be on my question list. It louder when trying to cool down a hot interior as opposed to a little cool air to maintain temperature....maybe when there is more load on the compressor. It's not super loud so many ,ight not notice.
CRS

 

Hey CRS I know you moved on from the XE, but did the dealer have anything to say about this? I have recently noticed the exact issue and it is very annoying once you notice it. And it's so much worse with the weather being over 100F outside.

RPM-dependent whine that only happens with the car interior hot and the AC on. Goes away a few moments after turning the AC off.

 

At idle and just off idle is when the torque is at its' lowest. Add the drag of a compressor and a lot of cars are designed to have a little bump of idle speed when the a/c kicks in. Are you perhaps seeing an extra 100rpm at idle? Maybe open the hood and listen while someone in the car gets the a/c to engage. If it's just a little whine I'd be likely to live with it - if there's any mechanical rattle or similar then I'd get the dealer to check it, starting with the simplest things - all the places the belt contacts.