Noisey When A/c Is Switched On - BMW Forum

BMW Aquarium · 07-26-2005, 09:34 AM

I just bought a 96 328IS and the only problem is with the A/C.
When I'm not running the A/C everything is quiet and sounds great. When I turn on the A/C I can hear something that sounds more like a rattle.
(I know what bearings sound like when they go bad.)
Anyone have any ideas about this? Blwer motor was just replaced before I bought it.

Thanks

SinSeven · 07-26-2005, 12:31 PM

It could be the compressor. I'm kind of experiencing the same problem, but mine is more of a "hissing" noise. Hope you get the anwer you're looking for.

sp0rky · 07-26-2005, 03:47 PM

BMW compressors ESPECIALLY get noisy with age. Sometimes it means they are going bad - sometimes it means they are simply old, but will last a while.

It's nothing to worry about unless it's on its way out - usually.

You can sometimes tell if its on its way out if the clutch on it starts to slip OR lock and cause belt squeak for a breif moment, or if cool air cuts out for a few seconds at a time, etc.

drz · 07-26-2005, 10:54 PM

Hmmmm. I have the same rattle, and I have heard it comeing from other E36s as well. I guess I will just let it be. You can get a new compressor from eBay for real cheap. http://cgi.ebay.com/ebaymotors/AC-Compress...1QQcmdZViewItem

Replacing it is not simple, so labor may cost you a bit. I will jst live with the rattle. I'll change it if it goes out.

cymorg · 07-27-2005, 04:38 PM

mine also makes sortof a hissing or whining noise when the a/c is on.

it blows decent amounts of air... i can live with it i suppose.

BMW Aquarium · 07-27-2005, 08:16 PM

I was talking to my wifes step father and he told me to put soapy water on the belts.
If that doesn't work then look to the tensioner and idoler.
Lastly the compressor.
As soon as I get back to KS I will try and see if it works.

drz · 07-27-2005, 11:21 PM

The soapy water thing is not really a fix. Check your belt for cracks or any other damage. If you notice anytyhing, replace the belt with a new one.

drz · 07-27-2005, 11:21 PM

I had the rattle on my car, replaced the belts, and still have the rattle.

cymorg · 07-28-2005, 05:05 PM

so will replacing the belts take away that hissing and moaning noise that I have?

camnipotent · 07-28-2005, 07:17 PM

I don't know for sure if that will work. I've had them all replaced and I get the compressor sound every time the A/C switches on, and from reading the other posts, it sounds like it is common. Every car, obviously, will make noise when the A/C switches on, but if it is obviously louder than it should be, take it tothe dealership for a quick quote. They shouldn't cost anything.

cymorg · 07-28-2005, 09:21 PM

yeah right every time i goto the dealer they charge me like craaazy

camnipotent · 07-28-2005, 10:33 PM

I'm talking about the quote will be free, not the service...hahaha. I know they would figure out what the problem is, and then you can get it fixed if you do it yourself for 1/3 of the price.

Gkamysz · 07-29-2005, 09:29 AM

Yeah, mine is loud outside the car, kind of hiss, no rattles though. The rattle could simply be a heat shield which is loose. When the air is on, the engine tends to shake more at idle. Does it rattle at 1000 RPM or more? I don't think mine is cooling very well at this point, but haven't checked the coolant yet.

camnipotent · 07-29-2005, 10:14 AM

A/C units always work better when you are moving anyway.

BMW Aquarium · 07-30-2005, 02:13 PM

I'm not sure if my A/C runs smoother at higher RPM.
I'm currently on vacation in Oregon. I will check on Sunday when I get back into town.
If I bought the part, how much would it cost to have a local shop swap out the old part and install the new one?