Ok, so I bought my 2002 Z06 a month or so ago, and now I’ve noticed something that I need some input on.
When I start the car, there is a ‘hissing’ sound ( best description ) that starts, kinda sounding like the HVAC system is on low but the system is off. It stays that way regardless if I turn the heater on or not. Even after it’s turned off, the sound remains.
I drove a 2003 Convertible a few weeks ago with the same climate control system on it and it didn’t do it.
Is there something WRONG with the car’s climate control system? I don’t notice it after I start driving, and it’s not really annoying, but just want to make sure that the car isn’t having issues.
TIA

 

First thought with a hissing sound is a vacuum leak but it wouldn't be there with the car turned off. How long does this sound last after its turned off? Refrigerant still pressuring down after shutting it down will make a little sound but it stops within about 30 seconds or so.

 

doesn't do it with the car off, but regardless if the heater/AC is on or off you hear it.

 

Then its most likely a vacuum leak under the dash that controls the HVAC air valves. You'll need to get in there to locate it. Make sure its not coming from the engine compartment first.