AC airflow dies on lowest setting
 

Okay, I just got my A/C recharged and it's ice cold now, but a weird problem appeared. When I drive the car for about half an hour with the A/C on the lowest setting, the air seems to stop blowing out of the vents. (You can still hear air flowing somewhere, but nothing comes out.) At that point I usually turn the A/C on the highest setting, and after about a minute, air starts flowing out of the vents again. It's really strange, because it sounds exactly the same whether or not the air is flowing out.... almost as if there's something physically blocking the flow. Also, this only happens with the lowest setting. The air doesn't have any flow problems with the higher settings.

Re: AC airflow dies on lowest setting
 

Did you replace the heater core recently? Maybe the box or surrounding piping didn't get aligned properly and air is leaking out?

Thomas.

I bet it's freezing up.
 

I had a buddy w/ a F-150 that would do it so bad that you could turn the heater on to blow out the vents, and little ice chunks would start pelting you ! :D


Not sure why they do it - dirty evaporator core, I guess. Overcharge might be another possibility.


Might be worth your while to see if the place that charged it has any ideas - if for some reason it is the core, I would imagine that labor would eat you alive to replace it.

Probably easier - and definitely cheaper :p - to live w/ it.


Britt

Re: AC airflow dies on lowest setting
 

I thought maybe something was freezing or misaligned too, but that doesn't seem to explain why the higher settings have no problem at all. From what I know, the shop just patched a leak and recharged. Is there anything that an A/C does differently after driving the car for a while (when it heats up)?

The way I understand it :
 

The higher blower settings don't allow this to occur since there is a larger volume of air blowing over the coil.


When that airflow decreases, voila !


After a quick search, here's a forum that might be of help :


http://www.autoacforum.com/searchresults.cfm


Interesting stuff - good luck ! :)

Britt

Re: AC airflow dies on lowest setting
 

http://shbox.com/1/vac_check_valve.jpg

Check this part. More than likely not the case, but I wouldn't rule it out. I just replaced mine, only $5-$6 from the dealership no less.

Re: AC airflow dies on lowest setting
 

Bring it back and have them recheck the charge. If it's a little low at slower fan speeds the evaporator could be freezing up - sometimes you can even hear it "crackling" as it thaws.

Re: AC airflow dies on lowest setting
 

Thanks again for all the info! I'll try those suggestions.