I have the original ac on the vehicle its a 2004 5.4 fx4 with 223000 on the clock. On my way back from Oregon I noticed the ac temp was becoming sporadic and while in Chandler when it was 103 the ac failed all at once(Its was getting real weak to that point.) so I have decided to just put a new one on. When I hooked the gauges up it was around 75 outside and the high side bumped to 145 the low side bumped all the was to nearly pegging out. I think I have a leak or reed valve failure. But keeping in mind I am going to evac system,Change out compressor, New accumulator and new condenser with O rings and using Nylog on them where is the expansion valve is it a metal one or one with the screen(Orifice tube)?