Questions and Answers

A Whining BMW 323i Q. Vince, I have a 2000 BMW 323i with about 30,000 miles on it. The climate control makes a slight "whining" noise when the air conditioning is turned on. The noise comes and goes with acceleration and deceleration but is still noticeable at an idle. I can hear a slight, but at times worse, "whining" noise that goes away when the air conditioning switch is turned off and returns when the air conditioning switch is turned on.

BMW repaired the problem about 6,000 miles ago. They replaced a "high side schrader valve", evacuated and recharged the system. They said the "schrader" valve was leaking and the system was improperly charged. The noise was gone after BMW performed this service but returned again about 2,000 miles later.

I have not returned to BMW. I would like to be more knowledgeable concerning this noise before I confront them again. The car was still under factory warranty when I took it to BMW but is not now. I think they should stand behind there repair and a little knowledge on my part might go a long way toward that.

Thanks in advance,
Jack

A. The HVAC in your vehicle is not vacuum operated, so it can't be a vacuum leak you are hearing. I guess it is possible for the A/C system to make a "whining" type noise if it's low on refrigerant. And a leaky Schrader valve would cause the A/C refrigerant to go low.

The fact it went away after being and recharged tends to support the fact that it is low refrigerant that is causing the noise. The fact it returned tends to support the fact that either the repair didn't hold or there is another leak in the system.