Hello, new member here. I have a 2002 pathfinder sec4x4 with 3.5 and a/t and 230k miles. I've been trying to diagnose an ac problem. The ac would be cold and work fine and then other times it will only blow hot air. I hooked up manifold gauges and I was getting high low pressure side #s (120 psi) and low high pressure # (under 90 psi). I suspected a possible clog. I evacuated and pulled vacum and refilled with as close to exact .99lb r134a as possible using scales. It then worked fine for a day then back to intermittent warm then cold. Usually if it was cold it would stay cold for the day even with starting and stopping the car running. When I pulled the vacum I held it for 1 hour and it dropped .5" mercury. I figured that could have been connection of manifold gauges. When the air was blowing hot the suction line was hot. So I again assumed clog. I replaced the condenser and expansion valve. Bingo, great very cold air. Now 2 days later I'm back to high low side pressure and low high side pressure. Static pressure with car off for 1 hour are 90/90 with ambient temperature of 80.
Any help would be greatly appreciated. Thank you
