SantaCruzS4vant

Recently I noticed a hissing noise coming from under the hood of my 5 week old 2001.5 US-spec s4 Avant. I'm not sure if this has been happening all along or not. Hiss is only noticeable after the car has been shut off and goes away in about 45 seconds or so. Thinking it was perhaps the AC compressor I left the Econ button for my commute this morning and still noticed the hiss. Someone please tell me this is normal and I don't have a busted hose or something worse.

Ferris TMK

is the hiss coming from there? If it is it's the A/C..

I had a problem where my A/C clutch was frozen so the compressor was always on. I got the hiss all the time. Turn the car on and listen for it with the A/C off is it there and is there condensation on the A/C lines( the two coming from the firewall)? Then have the dealer check the A/C compressor. If it's not now fire up the A/C, not in ECON mode, is it there? then it's normal...

UberVier

I've heard it continues to circulate coolant after the car is shut off if the temp is high enough, but it's never happened on my car, so I"m not sure.

ruxprncd

I have the same thing, also on a new S4, so I'd like to think it's normal...