I own a 1972 Buick Skylark GS which was rebuilt. The air conditioning unit used to work fine, but now it has grayish-white smoke pour out of the vent inside the car? At first I thought it could be water dripping somewhere on it from under the hood; however, it does it on a dry day, too. What's confusing is that sometimes it doesn't do it at all? I can't find a pattern to it. The entire inside of the car will fill up with smoke if I don't turn it off when it occurs. Fluid levels are checked, people have looked under the hood, everyone just scratches their head. If anyone wants to hazard a guess as to the reason, it'd be much appreciated. Thanks!
First, need to describe the smoke. Could it be "fog" from moisture in the A/C system? (heater core) Does it have an electrical smell? Or any Smell? Do all of your switches and fan controls work correctly? Does the fan make any noise or have any problems? I would probably check the fan relay mounted on the engine side with the wires going to it.
I'm not an a/c expert by any means but I've had a number of them apart and there is nothing inside the duct work of your a/c unit that could "smoke". It's got to be something else, or the smoke, if it is smoke, is coming from somewhere else under the dash. The only other thing I can think of that could cause smoke to come through the a/c ducts is if you had a big hole in the a/c box and you had something else smoking in the engine compartment and the fan is drawing it in, but you would certainly notice that with the hood open.
i am like carman, the only three things that can produce smoke like conditions from a air unit is 1. coolant leak in the heater core that makes steam that collects on the windshield and windows fogging them up ... 2. leaves or grass that has gone down from the air intake boxes to the resister coils that regulate blower speed , and when the coils heat up red hot like they do.. it sets the cumbustible material afire and makes the smoke come out in the inside of the car... but also smells like burning leaves.... 3. like already said , a pinhole in the evaporator or one of the pipes leading to it that lets referigerant out,, mixed with oil.... but that would be a one time thing....unless you were charging the unit at the time..... there is not supposed to be any wires inside the heater/ac unit except the blower resister... and blower air cools it to keep it from burning out.... I have to correct myself,,, a 4th thing can be a rat nest at the resister location.....
if it still blows cold after a while I doubt it's a leak. If there is no smell I doubt your burning something. Is it really humid when you run the AC? You will get the reverse of breath on a cold day. I'm going to say your system works wonderfully. or it maybe over charged or the poa valve is bad/not adjusted right. Does anyone know what the temp is supposed to be coming out of the vent?
Does the smoke have any odor to it? A slightly 'sweet' smell would indicate a coolant leak form the heater core. If it smells like burning leaves, there is crud built up near the resistor.
I want to thank those of you who responded to this dilemma so promptly. I really appreciate it! Lots of good ideas here for me to check out. I'll be flying to America (where my car is) in a month or 2 and will try to tackle the problem then. Cheers from England!
Something to consider here is the possibility that the "smoke" is actually steam, like water vapor. I have seen, particularly on the more humid days, that, if the system is working VERY well, that the air entering the plenum is chilled to the point that the humidity in the air is condensed out, and blown into the car. It, at times, appears to be like a smoke screen. If the "smoke" has no odor, it is not likely anything burning. Usually, coolant, oil or someting in the plenum stinks to the point where you have to open the windows, or get out of the car. Ray
Ray, thanks for your input. It's true, there's no odor to the smoke, but it just pours out the vents, filling the car. I'm over in England, but I think my EX is going to check out some of the suggestions given here on this thread, since my car sits in front of his house.
