When I turn my car off, I hear this hissing noise coming from the front (if you face the car forwards, it's at the top left). What could this be? Bad?

Also, in lieu of my OCD, today I parked (I'm an awful parallel parker) and the rear wheel is up on the curb when the rest of the car is on the street. Is this bad for the car if I leave it overnight? Also, I'm worried it screwed my rims up- but I don't think something like that could ever scratch them since the tire would hit the curb first correct?

Thanks,
A4

 

Its the ac system equalizing pressure. Its completly normal.

 

rear wheel is up on the curb when the rest of the car is on the street. Is this bad for the car if I leave it overnight? Also, I'm worried it screwed my rims up- but I don't think something like that could ever scratch them since the tire would hit the curb first correct?
not wise to park like that especially if you have low profile tyres they could puncture or weaken the tyre walls, I also agree with the A/C dumping pressure its normal