when I turn the car off, it sounds as if something is turning/grinding, almost like if you stuck something in a fan blade. I took it to the dealer, thinking I was still under warrenty, and they replaced the blower motor and charged me 200 bones. I drive it home, turn off the car, and there is the noise. After getting a run around, the tech listens to it with me and says it a normal noise when vacum is lost. I have never heard a car do this. Has any other Mustanger had this noise?