Short term air

[yostie5]

Hello all. Long time reader, first time poster. I have read posts on the blend door problem and have performed the diagnostics but still can't figure out why my ac only blows cold for about 20 min. (every time) and then cuts over to full heat. AC system checks out good. There is a musty sort of odor as the ac fades out and hot air blows in. If car sits for a couple hours ac is fine for another 20 min. Anyone ever run into this? Thanks,
Greg

95 atx no mods yet

 

[BlackOnBlackATX]

first you should try the eatc self test, the directions are on www.shotime.com, i think that can tell you something most likely. let us know man, good luck.

 

[projectSHO89]

Greg,

You have the classic symptom of an evaporator core freezing.

It is most often caused by a slight undercharge of refrigerant.

While you probably haven't been and won't be using your AC system by itself regularly in the winter, this is definately a problem you will want to repair when the real AC season arrives in 4-6 months.

You might have also notice that if you park the car when it fails (goes hot) and return an hour or so later, that there is a very large puddle of water under the car. This is the melted ice that drained from around the core.

Steve