99 Cherokee A/C low side pressure question

[WH23G3G]

I've got a 99 Cherokee XJ 4.0 with 203,000 miles. The A/C was evacuated twice 6 years ago when I worked for a shop and could do it easily. Up until now it's given no problems. It even still cools ok but the temp from the a/c registers definitely isn't what it use to be even on non-humid days. I just had time to do a low side pressure check and it's right on the border about 24-25 PSI and that was after using the A/C on a 15 mile trip. And it was only about 75 out and not humid. I know the proper low side pressure is 35 PSI. Nothing's freezing up to suspect a blockage so maybe it's slowly leaking somewhere over the years. I don't see any residue buildup at any of the connections so it mustve leaked out over the years. With this pressure noted should I add a can of some kinda freon with some oil mixed in with it or just leave it alone? We're about to head down to Florida in a couple weeks so I'm trying to avoid dumping large amounts of money and ruin my trip but also don't want to be sweating.

[A383Wing]

sounds like it's low on charge...maybe a small leak somewhere....

all AC systems will leak some...they are not totally sealed....leaks will occur at shaft seal and go through the rubber hoses

do not use freon in a can ....it has sealer in it and will plug your system...and shops will not work on a AC system with sealer in it.

[elacruze]

If you went 6 years without a recharge, you did well.

What's the high side pressure? 220-250psi after stabilizing is about right when ambient is 70-80*F. If your high side is low too, you simply lost some refrigerant. I agree that dime-store cans are not good economy. You should have it recharged at an A/C shop that can leak test it and look for potential problems like compressor joint failure or schrader valve leaks that are prone to worsen quickly when seeing high pressures after a recharge.

[WH23G3G]

I havent checked the a/c with a proper set of gauges. I plan on doing it tomorrow night after work. I've got to take it to my friends house because he works on a/c at the shop he works at and knows how to do it. I deliver parts to shops and they always buy the cans of freon from the parts stores. Most of them still use the can tapper and charging hose and not a machine. But they've been doing it for so long they probably know what to expect.