Hi , i just finished reading all the ac problems trying to find one with the same I have. I turn on my ac and start cooling fine, but after 5 min its not cooling anymore, the compressor still working, so i cheked the high and low side on the engine, the pressures are ok, but when the car stops cooling the low pressure goes to down totally. What the ac specialist told me is that the expansion valve es stucked, if a change only the expansion valve will solve my problem? and he told me that for changing the E.V. he needs two days for removing the hole dashboard? I saw that you can reach the E.V by removing the glovebox, but can it be replaced only removing that and the blowing motor ???
If the E.V. needs to be changed, what is the OEM part number and the cost in USA?
Sorry for me english but I am in Brazil. Here there isnt too much info on WRX. 2001 or support from the stealership

If your car is the same as our model year 2002, you can refer to this thread-
http://forums.nasioc.com/forums/showthread.php?postid=4179167
Follow the instructions for removing the AC evaporator, the expansion valve is in the same location and can be removed with that procedure. Disassembly of the dashboard and removal of the HVAC unit is not required, only the glovebox, blower housing and a few other things have to be removed. Done by someone who knows what they are doing it should take no more than a few hours.

the instructions are helpfull, but my problem is not cycling, my problem is that stops cooling and not cooling anymore, if you touch the low pressure line is not even cold.
My question is if with the change of the Expansion valve will solve my problem. If so what is the OEM part number.
Thanks.

The reason I linked you to that thread is not because of the freezing problem, I realized that is not your situation. I was pointing you to the instructions contained within that thread which explain how to get to the expansion valve without major disassembly. You can disregard the rest of the thread.
Your problem could be the expansion valve but since I can't check your car myself there is no way to give you an absolute answer. Only your local shop can do that.

thanks for the help, right now I need the OEM part number for the expansion valve, there is anyway of getting that online or by some dealer?
Thanks in advance.

Send a PM to Jamie at SubaruGenuineParts, link to this thread and explain what you need. She should be able to help you.

Has your AC been worked on recently?? Evacuated or recharged?? I used this to fix a horrible expansion valve problem I was having!! Works perfect now!! You should try it!!;)
http://i90.photobucket.com/albums/k256/crazygc8/DSCN0162.jpg

NO, my ac has not been used since Nov 06, and used it the day it stop cooling (last week) . My mechanic told me he opened various expansion valves that were clouged, so cleaning and adding oil could be a solution before change it. Until now i didn't dissasemble anything.
Thanks.