Hissing AirCon

[barryj]

My AirCon makes a hissing sound from time to time. Of course, when I got a mechanic have a listen, it wouldn't do it. Apart from carrying a mechanic around with me at all times, does anyone know how to cure this:

AirCon switched on (minimum temp, fan level 2), cruising along at 60ish, slow down to 50ish and then accelerate back up to 60ish. As the car accelerates, the aircon produces a hissing sound for a couple of seconds and then stops. Any ideas?

[cyrus1971]

Not sure about how to cure it mechanically. The hissing is probabaly due to the vacume operation / actuation for the ducts re-adjusting (foot, face, screen) rather than temp or blower speed.

Just an idea but one method is not to tinker with the settings. So it the unit does not have to re-set ?

[poorcardealer]

Could be that or it could be a minor leak..........rubber "O" rings expand and contract and upon contraction you can get a hissing noise, however if the system seems to operate well and its nice and cold (put a themometer in one of the vents in the car, turn the air con up full wait 5 mins and you should get a reading of between 5-9 if the system is working effeciently) then it probably nothing to worry about.