Saint_Berzerker

I guess it's fog...can't think of another word for it.

Anyways...it gets really hot here, and sometimes on long drives, a "mist" or "fog" starts coming from the ac vents. It happens on either ac settings (inside/outside air). The air will still be cold, but not that great.

If I turn the ac off or down for a few minutes, I'll turn it back on and it's usually fine for a while.

I don't know much about the ac system, so any help would be great.

terryjmatthew

Your evaporator box may be full of water.
Out of curiosity, Have you checked your coolant level recently? These are also signs of a possible leaking heater core. Do you notice any kind of smell when the problem is occuring?

seanz0rz

sounds like you have a restricted drip line.

had a similar problem in my honda, that was the problem. the little tube that allows the condensation to drip out was all caked with crud, only allowing a drop /10 mins, instead of it flowing freely.

Jonnym

my Tacoma used to do that when I lived in Austin, it was new, and only happened once in awhile. make sure you run the a/c pulling outside air in at least half the time- that's what the guys at the dealership told me to do when i got it.

Saint_Berzerker

I have plenty of coolant in the coolant tank, if that's what you mean.

No, there's no smell of any kind.

Evaporator box? Where's/What's that? how do I check that?

Would a high outside humidity cause this? Where I am in TX, it gets humid sometimes when it's really hot. But I've never seen it in any other car down here...so I dunno.

The drip line seems to be fine. When I park, I always notice a small puddle of water where the hose lets out, so I don't think it's clogged.

mastacox

NERD ALERT NERD ALERT

If it's really humid outside, it's possible that your ac is cooling the air past the dew point, and you're "flash condensing" the water in the air, creating a fog. I have had this happen a few times in my car too, only when its humid enough to do so.

How hot is it getting? If you had air that is 90 F and 80% humidity, the dew point is only about 82 F. So as long as your AC is colder than that (my guess is its much colder, around 60-70 F) you can be condensing the water in the air.

FYI, for the dew point for 90 F air to be 70 F, that would mean it's only 50% relative humidity outside.

Red3.slow

yep thats why mine does it especially right before during and a little while after summer showers where the humidity is about 70- 90%

ironroad9c1

just run the recirct posistion .

Saint_Berzerker

I looked in the factory service manual and it had a "troubleshooting" section about it, and they said that the cooling unit, the fins (whatever they are), could be clogged/dirty.

The ac has never been that great, even after the new engine, so I might check there next.

Thanks guys!

toyaholic

here here for the high humidity. my dad and i were rolling in his 98 tacoma the other day and this happened. perfectly normal, my other yotas do it as well. lots of humidity in the midsouth.

91_4x4runner

Mine has done the same thing on very humid mornings (it gets pretty humid in San Antonio).... I was really worried at first though it was still blowing cold air out... Turned it down and it stopped... tried again later during the day, and it was just fine.

Saint_Berzerker

Just doesn't make sense that no other cars do this, only yotas? weird.

Yeah...it gets the worst when I go to Houston...Home of humidiy hell.

Jimmeh

My moms 94 Escort did this a few days ago when the humidity was very high, and it was about 100 degrees.

mastacox

Any car can theoretically do it, it just needs cold enough AC... Yotas tend to have nice chilly AC!

86SR522REEFI

For a few years, and then like the paint, it goes away if not taken care of.

Cebby

Fog out of the AC vents was the beginning of the end for my 4Runner's AC. This was about 135K into my 4Runner's life.

toyaholic

yeah, i've seen plenty of other makes do the same thing, just so happens that all we own is toyotas.

Tdubbs05

i had that thing happen once while i was driving a friends 540 bmtroubleu. i was billowing smoke out the back but i couldn't see it at all because it was trapped in the vortex between the trunk and the ground. man and i thought i was so cool flying past ppl... started blowing the fog in and when i got off the freeway to check it out, a heatercore hose had blown open.

jerometry

the same thing happened to me when i was on the way to school. Now that i think about it was one of the most humid days here in socal. the air coming out was still cold just looked pretty freaky with this foggy misty stuff coming out.

dmatter

I personally like when that the Fog Comes out! It usually Occurs when I Run my Fan on Low Speed. Probably a Very Small Freeze Up From too Slow of a Speed Setting and The Right Outside Conditions