During hot (summer) weather, if I leave the car parked (unstarted) for more than a day, the AC will not get cold. When this happens the compresser functions fine. Usually the AC will work again the next morning. When this was happening one time I took it to an AC shop and he put gages on it and said the the pressure was equal on both sides so he thought the expansion valve was sticking fully open. All other times AC works fine.

 

Thoughts?

Scott

Were the pressures measured with compressor running? What were the numbers? Even with an open expansion valve there should be difference in pressures.

Compressor was running but I can't recall the pressures. I remember the mechanic said everything looked fine from the compressor side (including charge). The question was what would cause something like this, only when very hot outside (and inside the car).