Air Con - Hissing

Novice07 · 05-08-2007, 07:18 AM

Hi, I've just bought a 2nd hand Fiesta Zetec build date Sep 04 (private sale). I had it checked out by the RACQ before i bought it and also took it for a test drive and didn't hear any problmes with the air con. I've been driving it around now for over a week and i've been getting these funny periodic hissing noises from the dash vents when i drive with the air con on.... also when i turn the car off and the air con was on there is a very long and loud hissing sort of noise that goes on for about 30 - 45seconds when the car has been turned off. Does anyone else find they have this problem? or could this be a sign that my air con is on the way out?

Thanks for any advice

**Jastel** · 05-08-2007, 12:59 PM

In Falcons you can usually hear a bit of hissing just after the car is turned off but not normally while your driving.

svo347 · 05-08-2007, 01:10 PM

Its perfectly normal, its the tx valve regulating gas to your system. When you turn the car off, the differences in pressure between the high/low sides of the aircon system balance out

Ives · 05-08-2007, 02:28 PM

I normally get the "hiss" when I turn on the A/C for the first time in months. I also get it when I turn it off... so it's normal.

Novice07 · 06-08-2007, 12:32 PM

Cool, thanks for the info... this noise is the only let down i've found with the car.... but i'm glad that it doesn't seem to be the air con on the verge of breaking down... what a relief