AC Problem

[mrv568]

I have a 2005 Lincoln Aviator that the local Ford Dealer has replaced the AC compressor twice now on. The problem is it will get down to 45 degrees or so while driving down the highway (I am fine with this) in town side streets slow moving 50-53 degrees when vehicle sits at idle for 5-10 minutes the temp goes up to 62-65 degrees. (outside temp is 90 degrees) I have taken it back to the Ford Dealer twice now and they tell me this is normal... This vehicle has always had Ice Cold Air all the time until they replaced the original compressor a year ago. The temps listed above are with the AC on MAX and fan on high Dual zone cut off and digital temp control set to 60 degrees (the recirculate button is ON) If it makes any difference the temps do not change if the rear air is on or off. The digital ac thermometer is in the center vent closest to the driver.
I did go buy some ac gauges and hooked them up. At idle low side pressure is 32 psi and the high side pressure is at 280psi (temp outside was 90 degrees) When I rev up the engine to about 1500-1800 rpm the low side pressure drops to 20 psi and the high side pressure goes up to 350 psi.
Any Ideas here? This car heads to the beach in a couple of weeks...

 

[matt0248]

Does it work well then get worse the longer the AC runs? The low side pressures seem a little too low. Maybe the evaporator is freezing up. Try running your test again with the recirc off to see what happens. Also, make sure the condensor and radiator fins are not plugged with crap.