You need the health, armor and weapon cheats enabled to do this. It's really more of a joke than a cheat too!

Get a police cruiser, get on top of it, shoot the lights (make sure the lights go out) and once the lights are out get in the car.

Turn on the siren and then you will hear some sort of whale sounds.

Use the cheats above that I mentioned (but don't turn off the siren) and then the car should be fixed and yet still be making the noise.