AC vent problem - Maintenance and Repair Forum

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AC vent problem
Thursday, July 28, 2016 8:51 AM
I'm having a problem with my AC that I am hoping some other Cavalier owner recognizes and can help me with. I have a 2001 and a couple of years ago the recirculation vent door arm broke meaning that to change the AC or vent setting from being open/fresh to closed/recirculate, I have to get upside down on my head on the passenger side floor and flip the white plastic (broken) thing that used to be attached to the metal lever by hand. At the start of each summer, I change it to closed for maximum cooling as there is a big difference in how cold the AC is compared to when it used outside (hot) fresh air.

Anyway, over the past couple of weeks, I have noticed that the AC is only about half as cold as it should be, so I checked the refrigerant pressure and I don't believe the compressor is having any problems and seems to be acting and performing as it should. The system behaves like the door is open using fresh air, but I checked to make sure the thing is closed. Then, the other day when I was washing my car, I got done and when I got inside the passenger side floor was soaking wet and there was a big line of water on the floormat that looks like it came right in from the hose - but I have no idea how - and of course over 15+ years of washing the car every week - that has never happened before. So now I am really convinced that something is set to "open" that I want - and that I thought - was closed. But I have no way of seeing, feeling or knowing what or where that thing might be since the only vent door that I am aware of is the one controlled by the thing I am manually changing as described above.

So my question is - is there ANOTHER door that can be opened / closed further up into the bowels of the dashboard that would explain both the water coming in and the outside air type feeling from the AC recently? If so - where is it and how to I change it? I hate to start ripping out the whole dash or trying to stick my hands down the outside under the windshield washers without knowing what the problem is.

Thanks for any information, suggestions or advice.

Re: AC vent problem
Monday, August 01, 2016 1:04 PM
Does your vehicle have a sun roof? Was your car running with the A/C on while you washed it?
What were your refrigerant pressures? Were they with the A/C running or off? Do you have any idea what the temperature and humidity was when you checked?
Can you visually see the compressor engaging to verify it's running? Is there a puddle under your car when it does run to show that the HVAC case drain is not clogged and is draining properly?
Have you had your windshield replaced recently?

The main source of water leaks on a car that wasn't on (in my experience) are disconnected sun roof drain tubes and leaking windshields, normally after replacement when they're not sealed properly by the installer.
If the A/C was running, you could have a clogged drain tube that's causing the condensation from the evaporator core to overfill the HVAC case. People wash their cars all the time without the recirculation door (the one that stops fresh air from coming in) being closed, so I doubt that's your problem. You can always get in the car and let water run over the suspect area, then trace the water back from the floor to find where it's coming in. If it's a serious enough leak, it shouldn't take long to pinpoint.

Stupid question, but you did have all the doors and windows closed, right? (I have to ask, I've seen a lot of stupid people in my day)


THE .ORG IS MY KITCHEN!

Re: AC vent problem
Tuesday, August 02, 2016 9:57 AM

Is there a way to see / get to / clean - the AC evaporator coil from under the dash or without taking out the whole dash? I'd like to get a look at that thing. I was thinking maybe it was clogged with dust or mold or something.
Re: AC vent problem
Tuesday, August 02, 2016 10:28 AM
There are some products that are sold to clean mildew off of evaporators (normally a foaming product for eliminating smells coming from the vents) that you might be able to try. You can try spraying them in the drain tube or the blower motor inlet (granted you take it off recirculation mode). Some of the kits may come with a rubber plug and suggest drilling a hole in the HVAC case. I don't recommend that. There's a possibility that the drill could impact and puncture the evaporator or heater core causing you more problems than you started with. As for being able to physically see it and actually clean it by hand, I'm not aware of a way to do that without removing the HVAC case and disassembling it as you would to actually replace the evaporator.


THE .ORG IS MY KITCHEN!

Re: AC vent problem
Wednesday, August 03, 2016 8:32 AM

OK. Then how about this......Is there a way to get to the door/flap that controls the position of the temperature selection. In other words - at the end of the cable connected to the hot/cold knob? As I described above, the vacuum controlled arm for my fresh/recirculated air door is broken so I am already having to crawl upside down on my head to change that setting. I know that the compressor and frigid ice-cold air from the source is not the problem - and the air flow position vacuum selector still works fine. So I thought perhaps some of the many broken plastic pieces from the cracked and falling-apart dash board (up next to the windshield glass) may have fallen down into the defrost opening. So I have completely removed all of that and now have a big hole in the top of the dash. I was hoping to be able to (just like the evaporator) get to / see or manually ensure that that door/flap was in fact going all the way from one extreme (hot) to the other (cold). The hot sure as heck is hot, but like I wrote in my original post, the cold just - for some reason - isn't making it out of the vents.
Re: AC vent problem
Friday, August 05, 2016 5:45 AM
That looks like it might be accessible. Look left and above the blower motor, toward the center of the dash, if I'm looking at this parts diagram correctly.


THE .ORG IS MY KITCHEN!

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