Ih8mycar

About two years ago I was hit by a tall suv just behind the front drivers side tire but pretty high close to the hood. I took it to a body shop and got the body work fixed but after I got it back I noticed there was still a hissing sound coming from behind the driver side a/c vent but sounded like it was coming from under the hood near the firewall. I tried to file a comprehensive claim with progressive where I explained the issue and suggested that it sondes like a hissing sound possibly being caused by a pinched a/c hardline. The insurance company and body shop both stated that there are no a/c components in the area of the collision and that my compressor had probably gone bad and needed replacing. I insisted that this noise had never occurred before the collision and it had to be related. I had a dye test performed where they found there to be no leaks in the a/c lines. Still to this day whenever I turn on the a/c or heater, there’s a strenuous hissing/whistling sound coming from behind the drivers side ac vent. Everything works as it should but the noise is pretty obnoxious, I’m absolutely certain this has to be related to the collision as I’d never heard it before and heard it immediately upon starting my car after the collision. Any ideas?

EasyPhil

If you hear it in the car you can probably hear it outside of the car with the hood up. It could be the heater control valve a plastic part that will eventually break apart with age.

Kalakov222

I recently bought a W221-S500-UK-2006 model.

Hear hissing sound each time i switch on the AC, this is inside while sitting on Driver seat, near the vents area/ dashboard.

as EasyPhil says if its the "heater control valve" shouldnt there be any other symptoms ? If so, what should i look out for?