Smoke?? from a/c vent

I was wondering if it is a common problem on xj's for the a/c to overwork and blow fog type smoke from the vents. I think that is what it is, and it only happens after about a half an hour of driving. If this info is needed, its a 99 xj sport with 4.0 and auto.

Thanks for your help,

Ryan

Are you sure this isn't some kind of condensation? Does it have any kind of smell?

It's probably very humid outside when you see this 'smoke'. It's just the condensation of the moisture coming through the vents from outside. Of course, if it smells like melted plastic...

Well, it happens all the time, not dependant on humidity really. Just has to be hot enough to use the a/c. If I switch it to vent for a bit, it stays extremely cold and will eventually stop "smoking". I haven't tried leaving it on a/c to see if it will stop on its own because it worries me. It has no smell really, but I have noticed before it happens the a/c tends to heat up a bit.

any other ideas?

Ryan

OK. The only thing electical with the AC system is the compressor wiring, which is under the hood and dash (fuse panel, harness, etc.) and would not come from your vent, and the blower motor itself. Since the blower motor is working even when you turn the AC off BUT the 'smoke' stops and you don't smell it, it is probably OK too. You said that when you turn off the AC, it eventually stops. This is probably due to the air inside the vent system warming up above the 38 to 40 deg F required to condense moisture from the air. It would still feel cold, but not cold enough to cause the mist. Also, notice if it goes up or down as it comes out of the vents (fan on low). Fog will go down, smoke or steam will rise.

I would bet if you turn it to the recirculated air setting, the fog would eventually go away also, because you would be recirculating the dehumidified cabin air instead of bringing the outside air/humidity through the system. This would prove the AC system is working properly.

My Jeep and VW do this all the time. Again, you can smell smoke (or antifreeze if the heater core is leaking), but you cannot smell water vapor, fog, etc.

Do you think maybe it could be a leak in the evaporator? Mine was leaking and smoking and now I soon will be $900 lighter when I get it fixed!

My 99 Classic does the same thing you discribe. It looks like condensation to me.

Sometimes the condensation pan drain gets plugged up, which will increase the frost. Condensor leaks often have an oily smell. I worked refrigeration for years and am kind of tuned to the oil smell. Freon itself, has no (little odor) unless it comes in contact with fire, then smells like chlorine (sort of).

I'm bringing this post alive from way back...

My wife's '01 XJ is puffing smoke out of the AC vents. It's not really smoke, it doesn't have a smell, so nothing is burning. When the Jeep sits for 30 min to and hour when you restart it, a cloud of white vapor puffs out of the AC vents. Probably just condensation. Where is the condensation pan located so I can check to see if it is plugged, like the last post mentions?