Today I decided to try out one of those over the counter A/C recharge cans on our Forester & Impreza. I started with the Forester, as it was already warmed up. According to the chart on the back of the can, due to it being 80 outside, the low pressure side of the system should have been between 40 & 50 psi with the car warmed up & A/C blasting on high, making sure the compressor clutch is engaged. Well, following all that, the pressure in the system came up at about 26 psi. Great! I thought, I didn't just needlessly spend $35 dollars on this recharge can! Well, My original plan was to recharge both cars with one can, so I purchased a larger 22oz can. I followed the directions to a T, tilting the can between 12:00 & 3:00 positions & shaking every few seconds. I ended up dumping the whole can into the Forester & the pressure just stayed at 26 psi.... What gives?? If there were a leak, it shouldn't hold steady at 26, but if it took the entire contents of the can, why did the pressure stay the same?
After the can was gone, I warmed up the WRX & checked it's low pressure line w/ the gauge that came with the can & it ALSO measured at 26 psi...... Is there some sort of pressure threshold on our cars that I'm not aware of? Is it just coincidence that both cars read the same pressure & they are both low? I"m pretty sure it's not a fault of the gauge itself, as when the compressor would periodically turn off on the WRX, & the pressure would equalize with the high side, it would read up near 55 psi. As soon as the compressor came on, back down to 26. Any info on this would be a huge help! Need to get ready for our first summer in Texas!!
Edit: I should add, that even though the pressure did not seem to go up in the Forester's A/C system, it did seem to blow noticeably colder than it did before.... So I guess that's good?