well thers a few things that could do it.1 is that the system is actually overcharged but you saying it blew cool and now hot kinda knocks that out. 2 since you used a can and didnt have it actually serviced, you could have a bunch of air in the system. believe me ive seen both of those quite a few times. and 3 just low charge ( leak in the system) . easy way to do this is get pag oil with dye, put some in the system and let it run. get a black lamp and the leak will stick out like a sore thumb if its leaking good. the reason i say find the leak rather then plug it with the r134 stop leak is because that stuff coats the complete system with stop leak, not saying it will hurt it but it always could. just find the leak and fix it the correct way.
01 dodge ram 2500 4x4 quad cab long bed cummins, a few mods.
02 tj manual, sye, tom woods driveshaft, 4" rough country x joint lift
sitting on 33's, rear disc brake conversion, 8500lb winch,flush mounted leds, and flatty fenders thanks to evergreen offroad