My air con blew cold white mist and then stop working, only warm air coming out now. Is my AC evaporator gone bad? Or Freon leak? Any idea what could be wrong before I take it to the shop? Thanks

 

take a rock/pebble to the condenser?

 

Could be a number of things.

If I had to select one, my choice would be a leak in the evaporator. This is in the incoming air flow and could account for the white mist, which would be refrigerant (mixed with a little compressor oil).

To really know you'll have to have this looked into by a professsional auto tech.

There's not really anything you can do on your driveway to address this.

Arrange to get the car to a qualified shop.

In the meantime, avoid running the A/C system, the compressor. If it is a leak in the system there will be not enough refrigerant to circulate to carry compressor oil and the compressor could suffer from lack of proper lubrication.