Whining Aircon

Has anyone experience with air-con compressor noises ? Mine has recently started a faint whining noise - just audible at engine idle (eg waiting at traffic lights). It sound just like a slightly noisy bearing (which maybe is what it is) & disappears immediately the aircon is turned off. It doesn't appear to make any difference whether the engine is hot or cold or whether the aircon has been running for a while or not. The noise definitely appears to be coming from the compressor - although I've not managed to confirm yet whether its the belt drive end or further in. The aircon still works fine, but I'm wondering if there are preventive measures possible which could be done now before it gets worse & possibly more expensive. Any ideas ? Paul 2004 996 C2 40th Anniversary

I would think it is low on refrigerant. If the pressure is low, the pump will be noisy. Best bet is to get a re-gas, and see if it cures the problem.

Thanks Richard, I'll try & find a local aircon specialist for a pressure check & re-gas. How long should a well used system last before a top-up's needed ? Mine was last done about 3 yrs ago when the radiators were replaced under warranty Does anyone know any aircon people on the south side of Birmingham ? Regards & thanks, Paul 2004 996 C2 40th Anniversary

As Richard says; low refrigerant pressure does make the system noisy. If you take into account the number of joints in the aircon pipe work and the fact that the condencers get hit by debris it's pretty good for a charge to last 3 years. Very minor leaks should be sealed by an agent added when the system is regassed. If you dont have a local OPC or Indy who you trust then Kwikfit have the same machine as everyone else to purge and fill your aircon. Your aircon is probably made by Nippon so dont worry too much about anything not being "genuine porsche" Ask the fitter to ensure the system holds a Vacuum when purged before any money is spent refilling it.

Chris, thanks for the comments. I'll do a bit of ringing around tomorrow & see who charges what & ensure they do the leak check before re-gassing. Paul 2004 996 C2 40th Anniversary

System now regassed with 900g of refrigerant & a qty of the relevant lub oil - after sucking out the old gas & holding a vauum for a while without any signs of leaks. The air-con guy was a little surprised the system was noisy - as pressures were only slightly down on "optimimum", but the re-gas definitely improved the pressures (high pressure higher, low pressure lower) & reduced the temperature at the vents when temperature is set to "Lo". The "whining" noise & my paranoia about a future large bill have gone ! Re-gas was "only" £38 - better than I remember from a previous car ~ 4 yrs ago. Richard, Chris - thanks for pointing me in the right direction. Paul 2004 996 C2 40th Anniversary

Hi Paulus, Blimey £38 was good - was this through an independent or Kwik Fit ? angusr

Angus, it was via a local independant who operates in a fairly small area around the south side of Birmingham & has no problem keeping busy (Surprising !!). Good thing was that he really did appear to know his stuff, even if it did take an hour in total. (As a comparison, another local independant wanted £40 & the next alternative £59) Paul 2004 996 C2 40th Anniversary