I will change the alternator anyway because it is not only whistling, it is also causing an error message in the engine ecu (unlinke the old one), so no need to spend money for tests.

M62 engine has a different alternator (a watercooled one) unlike the N62.

Just want to ask about your experiences with aftermarket alternators for the N62 engine.

So if anyone of you has got an E53 4.4i N62 or 4.8is and already replaced the alternator, it would be great of you can take a video :-)