I'm trying to recharge the AC in my girlfriends 2003 V6. I have the refrigerant and the hose with the pressure gauge on it as well. When i hook up to the low side, it jumps to max pressure, if i turn the car on and turn on the AC, it stays at max. Do we have a different problem besides low refrigerant?

seems odd..... what is max psi on your gauge?

Also, turn on car, turn the AC on and then to max and coldest settings, then hook up the dial. Furthermore, what is the ambient temperature when you're doing this? The psi dial is sensitive to the ambient temperature, and most provide accurate readings for 75-85 degress I believe.

All this aside, if your gauge is constantly reading like 40+ psi, I'd say there's a block in the line somewhere causing pressure buildup, which is very bad, or your gauge is broken, or it's not hooked up properly.

^ note, if someone used that stop leak crap on the system before, a block is possible since that stuff can cake up in the lines from what i've heard and the entire system could need a flush.

Its a brand new gauge, and the temp outside is about 77, and i have the dial set to that. THe max on the dial is 90 psi, and its redlined. I did hook up the gauge and put the AC on max, and it didn't move. I wonder if it's overfilled and thats why it's not working.

Should i just let a bunch out, and see if the gauge drops? Couldn't hurt, since it isn't working anyway.

uhhh.... I think at 90 psi the system and lines would blow up.... I think the gauge might be broken. If someone else has another idea, feel free to correct me.

I just hooked it up to my WRX, and the gauge is most definitely not broken.

.... hrm..... I guess I'd try and vent the system and then see what the reading is. I think you might have a clogged line somewhere because someone probably used stop leak at some point, which will require more then a simple vent and refill for the long run.

Call and talk to the shop at a Hyundai dealership. My dealership told me 85 is normal for our cars with the ac on full blast. But I have not had a chance to fool with mine yet. Just don't start venting it out.

safe psi for the ac is something like 25-35 with the a/c on and at full blast.

yea i charged mine this weekend, due to the header install as i let out all the freeon lol, put it on max a/c threw it on the highest level and filled it, i think mine settled at 33 or so psi

Mine peaks when I check it to. And the car was bought new and only has like 10k miles on it. We know the gauge is fine as I checked it on 2 other vehicles.