Vent expelling vapor when AC ON

[Kaarmaa]

My right center vent on an '05 intermittently expels a visible cloud of what seems to be water vapor when the AC is on. Does anyone have any experience with this type of thing?

[jschuk]

I haven't seen that since moving to semi arid Colorado, but I have seen that happen in a couple of cars with really cold A/C when I lived in frequently humid Nebraska.

[Latigo]

I've only seen that with the AC on airplanes.

[1 Lucky Texan]

make sure the a/c drain is clear, maybe check the cabin air filter.

If you are marginally low on refrigerant, it might make this more likely. not sure.

[DavidPeab]

Here's what my 2000 OBW owner's manual says about the condition: Cooling and dehumidifying in high humidity and low temperature weather condition -
Under certain weather conditions (high relative humidity, low temperatures,
etc.) a small amount of water vapor emission from the air outlets
may be noticed. This condition is normal and does not indicate any
problem with the air conditioning system.

I've had this happen on other cars like my old Volvo. It concerned me at first too.

[marcc]

that happened to me recently driving through the NC mountains. it was raining, warm and i had the ac on about 70 f. weird to see, but it went away.

[plain OM]

On aircraft, the mist is "intentional". Because the air outside is so cold, the cabin would become a freezer if it wasn't heated. However, when air is heated the relative humidity goes down, making the environment uncomfortable, and potential dangerous (static). Consequently, water is added to the air circulation system using a very fine spray. If the air temperature is cool enough, the moisture condenses and can be seen coming out of the vent. It's essentially the same a fog.

With the car, water isn't being added, but cold air is being pushed into the cabin which, on a damp day, could have a lot of moisture suspended in the air. As a result, the cold air causes the moisture to condense, and the same "fog" is formed.

However, I would agree with 1 Lucky Texan on making sure the evaporator drain is working. The same effect as in airplanes could happen if there's an excess of moisture in the HVAC duct.

Otherwise, enjoy the fact that your AC is working very well!

[Kaarmaa]

Originally Posted by 1 Lucky Texan

make sure the a/c drain is clear, maybe check the cabin air filter.

If you are marginally low on refrigerant, it might make this more likely. not sure.

I think I may be a little low on refrigerant, as the ac cycles between real cold and the same temp as the car.