I too have an AC Leak. Pulled vac for about 45 minutes, tried filling system with a leak dye refrigerant. Low pressure switch came on, good pressure filled ~2 lbs and AC blew cold for a day. Next morning it was empty. Only saw a tiny bit of dye below the compressor, may have been from pulling out the can from the port too fast. AC

Pulled vac again for about 4 hours and pressure at -28 but was back at zero the next morning. Could this be leaking at the compressor with just a little dye there orat the evaporator? I am afraid to put more gas in but not sure what else to check either. How would you check if the evaporator is leaking, would you see any dye there?

Any help is appreciated!

 

Good Post. I'm sure someone on here can chime in, but it sounds like you have an AC Leak

 

yes it's a leak and if you saw dye by the compressor then it's either an o ring, line near the compressor or the compressor itself

Oh, WalMart has R134A for under $10 per can

 

Wow, that's a hell of a tip torque.

 

Probably a seal on the compressor, that's the usual case.
If you already used the dye, you can also get an ac leak sniffer or even cheaper a detector kit which has a blacklight and special glasses to find the leak easier. I found these at good ol canadian tire.
Have you tried the redtek leakstop from canadian tire/walmart? It's fine to mix into in your ac system, and as soon as theres a leak it forms a tight seal which also lubes the orings and such.
If the leak persists, replace the seals or orings that are leaking. Make sure to get the system evacuated before attempting any repairs.

If you don't see any leaks - you might want to start thinking about the low pressure switch, relays, fuses, evap, dryer, wiring, etc. You can do tests on most of these parts like making a jumper wire to the pressure switch (take it off right away if it engages so you dont damage the comp), replacing fuses and relays with ones that work, jumper wire to the compressor to make sure the clutch is engaging (just for a second or you could kill the compressor), and on and on.. Google and this forum are your 2 best friends!

 

Got around a 100k. Going to need a rebuilt pump. Try using a rubber hose (with the engine off!!) and put near the pump and lissen for a leak. Or Remove the belt and check the pulley for play.