Okay, the lines have been flushed (third time since I started on this) but the compressor still only runs for about two minutes, the air blows cold, and then pressure build up in the line causes the compressor to shut down. Once the excess pressure bleeds off the compressor kicks back in and the unit blows cold for about two minutes before the compressor again shuts down. The problem seems to be the expansion valve as everything else seems to check out okay; I've now replaced the valve twice but the problem still persists. Is it possible that both the Chrysler dealer and aftermarket expansion valves I've bought are faulty? Although I doubt it, would a MBZ valve be a better choice, or could someone recommend another source of valves?