Hey guys, I have a 93 xj cherokee with the original R12 A/C system on it. The system hasn’t ran in probably 17 years. I just got it going a few days ago. I replaced the condenser, condenser lines and accumulator. I checked the compressor and it seemed good so I chose to go with it. I didn’t change out the expansion valve or H block on the firewall. I flushed the system with A/C flush, added oil and recharged with R134A. The night that I got done with it I drove it and it cooled down to 40 from the vents. As days have went on its progressively gotten worse it seems. I re checked the charge with my gauges and at 91 degrees outside it was running 253 on the high side and about 55-60 on the low side. Now at 91 degrees outside temp I’m getting 80-78 degrees out of my vents per infrared thermometer. Can someone help me out please?

thanks

 

Did you draw a vacuum on the system before charging r134a in, and did you replace the receiver dryer?

 

yes, pulled good vacuum and held for over an hour. And yes, new dryer/accumulator

 

Well those pressures seem like you're fairly overcharged. Honestly, if it were mine I'd have converted it to R-152a. I did a writeup on it on the S10 forum. But that's not going to help you currently. Drop pressure on the low side until it gets to around 40, maybe 30# and see how it goes. Also, pinch off a heater hose to make sure it's not a blend door issue (but the pressure is telling me we're probably overcharged).

 

Does your system have a TXV. It looks like a brass block with a Chinese hat on it

 

Those pressures do seem a bit high. It is better to be a little undercharged than overcharged. How much refrigerant did you put in?

Worst case scenario, evacuate the system, draw a vacuum on it to make sure, then recharge it. Verify what the factory calls for as far as refrigerant capacity. Put in about 70 percent of what is called for and see where your pressures are at.