2007 Explorer has weak AC. When driving at speed, the AC can produce reasonably cool air. When stopped at traffic lights or such, the air warms to ambient temps rather quickly.
I hooked up the pressure manifold and got:
- AC off at idle speed: 105/105 (low/high ports)
- AC compressor on at idle speed:70/120
- AC compressor on at 3k rpms: 40/175
Ambient temp was 86 degrees with 65% relative humidity.
Exact measurements vary when repeated, but are all similar.
My first thought was that it was low on refrigerant, but I'm reluctant to add any when the low side is already at 70 psi at idle and 40 when at 3k rpms. The high pressure port is lower than I would expect.
This leads me to think there could be a blockage somewhere? Any suggestions?