Alternator Noise

[youngdoc1]

Hi all,

I recently brought my 128i into the shop for a mild whirring / whining noise at low rpm under engine load. It kind of sounds like a turbo spooling or a sucking noise between 1000-2000 rpm, and it's been steady for the past year or so.

Mechanic diagnosed it as faulty alternator bearings. When I put a screwdriver to the alternator and hold my ear to it at idle it's exactly the noise that I hear during load. Otherwise alternator is functioning well, no electrical symptoms, and I can probably live with the noise - it's pretty mild and I've gotten used to it at this point.

My question is - is there any harm in leaving it until the symptoms get much worse, or until the alternator fails?

My options are: new OEM part ($965 + $20 for bolts) + 1.5 hours labour, used part ($100-250 on eBay - from salvage cars with varying mileage - a lot with around the same mileage or higher mileage than my car).

Are there any other options for getting the part cheaper?

Thanks for your advice!

(P.S. I live in Canada, and the car is a 2009 128i with ~60k miles).

[youngdoc1]

Bump

[maruzo]

Did u ever fix that whining noise?

My 128i is giving off that noise and I’ve been racking my brain trying to figure it out.

I did get the battery warning icon twice in the last week. Maybe the alternator is failing?

[kinyo]

Had noisy alternator. Sound like rattle though, not whining, at idle. Turns out to be defective alternator pulley. Had to buy a pulley AND a special tool to remove it.

[MightyMouseTech]

Originally Posted by youngdoc1

Hi all,

I recently brought my 128i into the shop for a mild whirring / whining noise at low rpm under engine load. It kind of sounds like a turbo spooling or a sucking noise between 1000-2000 rpm, and it's been steady for the past year or so.

Mechanic diagnosed it as faulty alternator bearings. When I put a screwdriver to the alternator and hold my ear to it at idle it's exactly the noise that I hear during load. Otherwise alternator is functioning well, no electrical symptoms, and I can probably live with the noise - it's pretty mild and I've gotten used to it at this point.

My question is - is there any harm in leaving it until the symptoms get much worse, or until the alternator fails?

My options are: new OEM part ($965 + $20 for bolts) + 1.5 hours labour, used part ($100-250 on eBay - from salvage cars with varying mileage - a lot with around the same mileage or higher mileage than my car).

Are there any other options for getting the part cheaper?

Thanks for your advice!

(P.S. I live in Canada, and the car is a 2009 128i with ~60k miles).

Had a noisy bearing on my 328 alternator. Cheapest option was a brand new Valeo (OE supplier) from Rockauto. Works perfect. You will also need the four aluminum bolts that secure it. Double check your amp rating, most likely 180 amp.

Oops, sorry, quoted wrong post.