wierd Air Conditioner problem in '94 318 is

[ultraviolet353]

I just bought a used BMW 318 IS with 118K miles. Everything is working great, even the air conditioner; however when I run the air conditioner, when I park and turn the car off approximately 3-4 minutes after the car is turned off I hear a high pitched (excuse the expression) fart-like noise that lasts for three or four seconds. Almost like the car is breathing a high pitch sigh of relief. Does anyone know what this is? I am guessing it has to to with the air conditioner since it only occurs after I run it.

[jcupy]

I have exactly the same car, similar K's and identical problems!
as well as a transmission noise in 1st and 2nd gear that sounds like a chain is loose and a rattle noise.
Gets me wondering if I should change cars....
Also I have a problem with my 10stack CD skipping all the time. I put in the CD cleaner disc and that plays fine without skipping. but other discs skips like mad whilst moving, even on smooth roads.