AC/Defogger Noise & Smoke

airconditioning

#1

I’ve begun hearing a strange noise when the ac or defogger is in use. It makes a ssshhhhh sound. Then as I was driving white smoke began coming out of the vents. Before I take to mechanic can anyone give me some info on what could be wrong? I drive a 2005 pontiac vibe


#2
The sound is likely a leak.  Three things can leak in there.  Coolant (the heater core or hoses)  Refrigerant from the A/C or air from the blend doors that are operated on a vacuum.  

The cheapest would likely be the blend door, but it would not make the smoke.  Either of the other two could make the smoke. 

Does the smoke smell sweet?

#3

Your description of the hissing sound is too vague to be of any use. I won’t even try to guess.

The “white smoke” that you sometimes see is no doubt just water vapor. It is like seeing your breath on a cold day. It occurs whenever warm, moist air meets cold, dry air. It is harmless and it even provides assurance that your A/C is working strongly.

Since you have no real complaints about your A/C’s operation you might even change your mind about going for service.