Can anybody tell me why there is smoke/fog coming out of my a/c vents when I turn on the a/c? I have a 90 Civic sedan. Thanks for any help.

 

Does it do it constantly or just initially? Most times what you are seeing is the reaction between hot and cold air and it looks like a smoke/fog

 

only time I ever had smoke come out of my vents was when the resistor for the blower motor burnt up. Blower motor went at the same time too though. If the fan still blows your problem probably isn't the same.

on a side note, when I replaced everything I did the blower motor first. It would come on, but only on the highest fan setting until the resistor was replaced.

more info maybe? does it smell like coolant or electrical?

 

could be the heater core but actual smoke sounds pretty extreme...

 

is it smoke- like fire smoke- or steam- like colant burning or a messed up heater core-?

 

It's pretty much initially. It's not electrical smoke it's like when you can see your breath during the winter smoke. When I have the lever set to allow outside air in, it smokes. When I set it to recirculate the inside air, it stops. Seems like it must have something to do with the humidity in the outside air I guess. Just didn't want it to be leaking. Especially at the cost of R-12 refrig these days! Thanks.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CRX Toad &raquo;</TD></TR><TR><TD CLASS="quote"> Most times what you are seeing is the reaction between hot and cold air and it looks like a smoke/fog</TD></TR></TABLE>

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dbailey &raquo;</TD></TR><TR><TD CLASS="quote">It's not electrical smoke it's like when you can see your breath during the winter smoke.
Seems like it must have something to do with the humidity in the outside air I guess. </TD></TR></TABLE>

That is your answer

 

That's so weird though. Why wouldn't other cars do it too I wonder?

 

I acctually got some smoke coming out of my vents in my RX-7. It was after about three hours straight on the highway with the a/c set all the way cold, and the fan set low lol. The air was ICE cold and I was coming some into some more humid air. I'd never heard of it happening either. Maybe it's an R12 thing.

 

I live in GA... plenty of humidity here.. This is a pretty normal phenomenon..

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by dbailey &raquo;</TD></TR><TR><TD CLASS="quote">That's so weird though. Why wouldn't other cars do it too I wonder? </TD></TR></TABLE>

I've seen it happen on all kinds of cars. If you're introducing air into the cabin that's the same temp. as the ambient dew point temp., the air will condense, causing the "fog" that you see.

So let's say the dew point is 60F and your air con system is blowing out 60F air. You may see condensation blowing from your vents initially. The reason this disappears is that your A/C will lower the dew point as well, drying the air out.

 

I love this site! Thanks to all for throwing in their two cents. I learned something new today like I always do everyday. Awesome!

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by wiZCo &raquo;</TD></TR><TR><TD CLASS="quote">

I've seen it happen on all kinds of cars. If you're introducing air into the cabin that's the same temp. as the ambient dew point temp., the air will condense, causing the "fog" that you see.

So let's say the dew point is 60F and your air con system is blowing out 60F air. You may see condensation blowing from your vents initially. The reason this disappears is that your A/C will lower the dew point as well, drying the air out. </TD></TR></TABLE>

Wow dude, didn't think you had it in you! That is correct.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SIred91 &raquo;</TD></TR><TR><TD CLASS="quote">

Wow dude, didn't think you had it in you! That is correct.</TD></TR></TABLE>

I have a Master's in Meteorology, it's child's play.

 

You guys are so awesome ! Thank you.. You would think the condensation on the windows would have been a clue. I was about to HAVE A HEART ATTACK. Time to take the van in for oil change anyway...