I have a 2000 C70 HPT coupe - and all is well except my airconditioning makes a terrible knocking and wheezing noise when the climate control is set on "cold". I can hear the noise coming from behing the centre console and stereo, under the dashboard. Unfortunately, the noise is intermittent, and everytime I try to take it to the Volvo dealer, strangely it doesn't make the noise so the technicians aren't sure how to look for the problem. Help!! The noise is so irritating and I can't seem to figure how to solve the problem. However, when I switch off the "cold" setting, and the fan is just sending warm air, the sounds stop.

Thanks much in advance.

Have they checked the Orface tube?

Hi Tech, will ask the dealer on the tube - but sadly the a/c doesnt just make the wheezing noise, it also makes a knocking and rattling sound, on and off at regular intervals. Do you think that is also an orface tube prob? Weird that the sound is only on when I switch on the a/c - there is no noise at all when the fan is on without the a/c. Thanks so much for yr insight and prompt response - I ve tried taking it to the dealer 4 times now, and on each of those occasions, the a/c was perfectly behaved - so the dealer didnt know what to check out. I fear my car may have a mind of it's own, ha ha.

Sometimes the compressors are noisey.They can still last for years.
The orface tube makes the weezing noise.
The compressor sounds like is cycling because it is low on freon.
You can ask them to try to add a little bit of oil to try to quiet it down some.