[Hej]

One of the things I've noticed on my car is a slight whine when the AC is running. It seems to be a little more prominent once the car is warmed up. It turns into a fairly obnoxious lower frequency whistle at about 1300 and again at 1800 rpm. It also seems to be louder when the engine is under load (i.e. I can't hear it if I rev the engine in neutral, but cruising around it's noticable). Seems like it's almost certainly either the alternator or the AC compressor. Has anybody else noticed this noise in their cars? It drives me nuts when I'm rolling around for long periods of time where the speed limit tends to keep my RPM's in ranges where the noise is the most noticable. But it drives me even crazier that most people (including the BMW techs) can't/don't notice it.

[MX20]

Got something like that with my old car. It was a loss in AC fluid (normal or not - don't know).
Whenever I got that, I went to my mechanic and he topped the level. Noise went out after that and came back in like 6 months. Rinse, repeat.

[E36E46E90]

There is a TSB for it or something. I believe they address in it the latest progman version.

[Hej]

Originally Posted by E36E46E90

There is a TSB for it or something. I believe they address in it the latest progman version.

Do you have any more specific information about the TSB, so that I can refer my SA to it if I go talk to him?

[Joe Bimmer]

Originally Posted by Hej

Do you have any more specific information about the TSB, so that I can refer my SA to it if I go talk to him?

+1. I'm starting to notice this as well -- seems to be coming from the passenger side of the engine bay at low RPM's.

[Hej]

Originally Posted by MX20

Got something like that with my old car. It was a loss in AC fluid (normal or not - don't know).
Whenever I got that, I went to my mechanic and he topped the level. Noise went out after that and came back in like 6 months. Rinse, repeat.

By AC fluid, are you referring to the air conditioning refridgerant? That stuff is supposed to be permanent, barring any leaks of the AC system. Loss of refridgerant is definately a defect. They should be fixing the leak instead of just topping it off repeatedly, if your car is under warranty.

[Hej]

Originally Posted by Hej

Do you have any more specific information about the TSB, so that I can refer my SA to it if I go talk to him?

Bueller? Bueller?

Anybody know if there is a good resource on the net where I can look up TSB's myself? Google wasn't especially helpful.

[BlueLion]

I know this is an old thread....but I am getting this same exact problem now.....i took it to the dealer today and they told me that the loaner 335 they have does this took and its not a problem they can fix.....does anyone have any info on the
TSB.....or did anyone ever find out a fix for this...

[BlueLion]

i hate to keep bringing this old thread back up but does anyone else have this problem and if so, what is causing the problem.....it happens almost everyday, except when I go to the dealer.

[Swamp55]

OK, I'll take a turn at resurrecting this old thread...

Has anyone else had this issue and had it fixed? My 9-month old '08 328i has begun to exhibit this whining or whistling sound at low RPMs. It rises and falls with light throttle variations, and is only present at relatively low RPMs. I can hear it plainly, if softly, even with the windows up. As for now, the only cure is the radio!

[johnc_22]

I have it also while my car is at the dealer getting a new camshaft (different story) I've been told it is "normal" and is the alternator.

[johnc_22]

This noise is getting truly annoying - next time I go for an elective oil change I'll ask them to check it and the A/C again since it doesn't seem to cool very well when the weather's warm. I'm pretty sure I would have noticed this noise when the car was new if it was there.

[BlueLion]

Originally Posted by johnc_22

This noise is getting truly annoying - next time I go for an elective oil change I'll ask them to check it and the A/C again since it doesn't seem to cool very well when the weather's warm. I'm pretty sure I would have noticed this noise when the car was new if it was there.

Let us know what they tell you, mine has yet to admit it is a problem.....

[E90330iS]

now that u said it..

[coetzejg]

Did you guys ever found an answer to this aircon whine? I have a '10 3.0 z4 and the aircon whine, when it above 25 degrees C outside temp, drives me nuts!

[hookah66]

I have this issue when my top is down, i.e. there is a slight whine/whistling noise, but not from a/c, it seems like the hvac dampers is trying to modulate the air flow in convertible mode. It goes away when fan is in OFF. It gets more prominent w/ a/c compressor ON. It goes away when I force to higher speeds of fan. I am gonna yank the cabin filter out and see if it makes any difference.

[galahad05]

If it varies with engine RPMs, then it could be the AC clutch. The AC compressor get's clutched in and out to save power/wear and tear when not needed in the cooling cycle. This can (sometimes) get noisy.

This is what I've heard, any way.

[sosas07335i]

when i first picked up my cpo 07 335i i had a similiar noise in the passanger wheel well. i would say it was more of a humming but i breought it in and they replaced the whole fan unit

[xDrive35i]

Alright now I'm experiencing this.

I come from the F25 X3 thread. After my first X3 was lemoned, I just received my replacement a few days ago, and I experienced the exact same problem. My floor mats (and underneath them) are very very very damp as well. I don't know if these are related.

[mike3000fl]

this is the ac fan blower rusting.

it is behind the dash to the left of the glovebox. it is rusting because your windshield and/or windshield cowl is leaking.

the water runs into the same place where the ac microfilter is, then it runs down onto the ac blower and rusts it out, then to your carpet.

to confirm this, wait for it to rain hard one day. take the car somewhere dry like a garage. remove the cover for the microfilter, take a look inside with a flashlight, look for water.

[grandmaster]

Originally Posted by Hej

One of the things I've noticed on my car is a slight whine when the AC is running. It seems to be a little more prominent once the car is warmed up. It turns into a fairly obnoxious lower frequency whistle at about 1300 and again at 1800 rpm. It also seems to be louder when the engine is under load (i.e. I can't hear it if I rev the engine in neutral, but cruising around it's noticable). Seems like it's almost certainly either the alternator or the AC compressor. Has anybody else noticed this noise in their cars? It drives me nuts when I'm rolling around for long periods of time where the speed limit tends to keep my RPM's in ranges where the noise is the most noticable. But it drives me even crazier that most people (including the BMW techs) can't/don't notice it.

My car started doing this recently. Has anyone had success in fixing this problem? I don't think it's the interior fan as the noise only occurs when the AC is turned on. The fan at all speeds is quiet if the AC is off. Once the AC is turned on, the whine changes with engine RPM as the original poster stated -and very noticable at low rpm. The sound is similar to alternator whine coming through the stereo, for comparison, except it's from under the dash. Does the 3 series have a second fan inside the car activated when the AC is turned on?

[doogee]

Same noise here. Slightly annoying.