Engine whine e70 4.8

[jfoj]

Is the whine actually from under the hood?

The reason I as this question is often if there is a bad ground you can get AC ripple from the alternator that then is amplified by the audio system and can be heard in the cabin as a faint background whine that will increase with RPM.

Usually this is due to a bad connection or ground wire loose.

The problem/trick is if you are not aware that there can be whine from the audio system, if you remove the alternator belt, the whine will go away and you might think the problem is the alternator.

Assume you have removed belt(s) in an attempt to isolate the problem?

You might see if there is a amplifier fuse that you can pull to isolate the audio system.