Bad Alternator? [Archive] - Bimmerfest - BMW Forums

: Bad Alternator?

09-15-2012, 04:38 AM
Hello Fellow Festers! I just got my 07 750li about a month ago and theres this odd rattling noise when idling or accelerating. Performance is the same beside the occasional tranny jolt (common problem?) I went in for an oil change and the mechanic told me he thinks the alternator is going bad. Anyone had a similar experience? I looked up the part #12317542935 which is supposed to be the alternator for my model. Is this air or water cooled? The noise makes her sound like she's gargling trash and rocks. I love my baby and refuse to drive her in this condition. Any help would be greatly appreciated! I'll see can I atleast record some audio of the sound so you guys can hear it. Thanks!

09-15-2012, 11:53 AM
Common problem, bearing in alternator is bad. Give BMW your vin number and they can let you know the correct part for your car.

Then you can shop for it. My car the alternator being replaced was 1100.00

09-15-2012, 03:35 PM
Wow 1100 really? I found the part by putting in my vin and it only costs like 300.00 bucks REM. You must've let the dealer find and install the part?

09-15-2012, 03:54 PM
No, I have an 02 180 amp water cooled alternator it was 700.00 for the remanufactured part from Bosch. 3 hours laborious tax. BMW wanted 1800.00 I let my Indy install it.

09-17-2012, 08:04 PM
I'm looking to order an alternatornasnwell I was looking at one by quality built with a 2 year warranty

09-18-2012, 01:25 PM
I ordered one yesterday from RockAuto. Should be here by Wednesday.

09-22-2012, 09:58 AM
It actually was the water pump going bad. BMW indys in Philly PA told me it was the alternator too.... Anyhow had it replaced by the goodfellas at MD Motorwerke in NJ. Car runs great now and is MUCH quieter. They even were able to code my 7 for me which another BMW Specialist wasnt able to do (could only read the codes!?). :thumbup: