i have this hiss noise when turning the a/c on since i bought the car . now, after 2 years with the a/c working perfectly but noisy, the compressor is ready to die soon, even turning the a/c off it keeps making a blender noise and it smells like something burning up.. real weird. i'm afraid now. this thing can lock up and mess up with belts, hoses, evaporator, condenser .... =(