I have an 2010, 6mt with the same exact whining noise. Most apparent from 0-3500 rpms.
When looking to buy my car I test drove about a dozen 2009/2010 328i E90s and never heard the whining sound until I picked up my car in Munich.
Even drove 2 more E90s since then and no whine.
My dealers explanation was BMW switched to a 'new model' clutch driven alternator mid 2010 production which is 'better' but has the noticeable whine.
The shop foreman said the noise was 'normal' and he has heard it on several other 2010 -2011 3 series, yet the E90 loaner we drove in Together had no such whine.
Believe me, this sound is annoying and sounds nothing like the cars I test drove, which is disappointing to say the least.
Instead of hearing the beautiful sound of the engine revving, you get treated with this cheap sounding, annoying whine.
The noise can be drowned out with moderate radio volume, but that's not the point.
Working on getting my alternator replaced or finding a solution of reducing / eliminating the whine.
2015 F15 X5 xdrive35i | Space Grey | Black | ZDH | ZDA | ZLP | ZLS | ZPP | ZDB | Bang & Olufsen | 19" Style 449 Wheels
2009 E90 335i | Jet Black | Black | Premium | Sport | 6spd
2010 E90 328i | ED 2.16.10 | PCD 4.9.10 | Space Grey | Saddle | Premium | Sport | 6spd | Logic7 | iDrive | Xenons | Sirius
2010 E90 ED Write-up 02.16.10
Last edited by gt0279a; 02-19-2011 at 08:03 PM.