This probably belongs in the EJ20t forum, but it might be my coolant pressure, so here goes...

My A/C is on full blast on my highway drives, set all the way to the blue dot and fan level "3." However, the temperature of air coming out of the vents is not constant cold; it seems to cycle from warm to really really cold with a period of about 2 minutes. I've got the left vent turned so that it blows directly on my left hand, and it seems to go from room/cabin temp to so cold that my knuckles ache and back to normal temp again, over and over. I've tried turning the "temp control" to various points on the dial, and it seems to be steadily warm at that point, but at full cold it still seems to "cycle" the temp on a steady rythym. This is an 02 WRX with 28k miles on it, never had the A/C serviced. Suggesions?

 

Go to dealership. you are under warranty right?

 

I have had about the same complaint with my car - the time between AC cycles seems to be too long - I notice it much more after my car has had a chance to warm up by sitting in the sun all day - I have had one dealership literally service the system four times - first time, they said it was overcharged, second time, undercharged, third time, overcharged, then the fourth time, undercharged... I went to a different dealership to give them a shot - they said that it was (drum roll please) overcharged, but after they fixed it, it works much better (not "perfect", but much better - also, to keep the performance of the system in perspective, my wifes car (about the same age as my 02 WRX) has literally twice the refrigerant that the WRX does - it does work better.

So - I think to a degree, less than spectacular performance is more or less the name of the game when it comes to the WRX AC - it's a small system. I have read that insulating the lines by the intercooler/turbo helps, but I haven't tried that yet. Also - I see many people state their AC blows very, very cold, but I haven't seen someone from the southwest say that...

 

My A/C has always been extremely cold, once it gets up to pressure; I wrapped the low-pressure (cold) line in the engine bay with pipe insulation, and that really seemed to help. The problem is not the temp, but the consistency; the fact that it still gets cold in the first place seems to say that there isn't a pressure problem -- otherwise it would simply never get cold. Instead, the cycling nature of the temp seems to indicate that I might have a compressor problem, or worse.

Hmmm... so tempting just to rip the entire system out and just drive with the windows down...

 

It is normal for the compressor to cycle. If it didn't the system would ice up. In fact there is an icing problem with the 02's and Subaru has a TSB on it, they have an updated thermoswitch that gets installed in the evaporator to replace the original one.

 

I'm glad you mentioned that -- this was actually the first thing I thought of, that the A/C has a "defrost" cycle and was trying to prevent icing up. However, it goes from hot to cold and back so rapidly; I would think it would just stay hot for a while and then go cold again.

Hmm, sounds like it is time to go to the dealer. I now have three outstanding TSBs (thermoswitch, driver seat bolt, cruise control clamp) to be taken care of...

 

The bolt and cruise control things are recalls and will be done for free (and they are ridiculously simple). The thermoswitch TSB is NOT a recall and won't be done free unless you are still under warranty. Your car would also have to be within the specific range of VIN #'s affected.

 

does anyone have access to this TSB? i unfortunately am in the EXACT same boat with my 02.

 

AC TSB info-
http://forums.nasioc.com/forums/show...postid=4246184