air conditiong not holding a charge on 1999 Jeep Cherokee

My 99 jeep held an air conditiong charge for 3 months. I just re charged it {with stop leak} It held 1 day and then back to blowing hot air. I just had it hooked up to diagnose and they found nothing wrong. Believe that. I also noticed the defroster works poorly in the winter. Any ideas? Thanks. Jennie

Asked by for the 1999 Jeep Cherokee
Replace the evap. Pat is correct. REPLACE THE EVAPORATOR!!!!!!!!
You know you can believe what you want to believe. My 38 years of experience has been in Southwest Florida, I'm very experienced in A/C repair. Finding A/C leaks is not for a inexperience tech. You need to have a expert look at it. That may be hard to find in PA. Replace the EVAP!!!! I've used dye, snifffer on a vehicle like yours and didn't detect a leak under the hood anywhere. Pulled the HVAC assy. & the EVAP was leaking. You can rate this answer whatever way you want. The reality is if you have no detectable leaks outside the EVAP, you have an EVAP leak!!
3 more answers
Air conditioning works on high pressure only a small leak quickly causes a drop in pressure. It is often hard to locate air conditioning refrigerant leaks. There is a refrigerant that has dye in it that helps locate a leak. After recharging the air conditioning with the dye if the system leaks it leaves a stain to help locate the source of the leak. A "sniffer can also be used to locate leaks, it acts like a geiger counter as you locate the leak the "sniffer" beeps loudly.In either either case the system will need to be evacuated have the leak repaired and recharged with refrigerant and the proper lubricant.
bad ac evapcore
sounds like your compressor might be clogged or something else under the dashbored