steaknchz

Last weekend I replaced my ac evap core and heater core after a mechanic I know told me that the evap core was what was wrong with my ac. After filling it up with freon it still blows only hot air. The compressor clutch is on but I do hear a hissing coming from it, I tried playing with the ac lines to see if I could hear anything from them or if they were leaking and they don't seem to be. The blend door actuator seems to be working and i'm wondering what my next step should be or if you guys have any advice. It's a 2000 XJ.

EatonXJ

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Did you get some gauge and a pump and pull a vacuum on it before you recharged it? Does the compressor cycle on and off or just stay on?

steaknchz

I got all of the pressure out before i recharged it and i used the gauge that came with the ac pro recharge bottle, i got it to about 40 psi with one can and it's down to 30 psi today, i'm sure i'll need another can to fill it up completely but with one can it should be at least a tiny bit cool than room temp i'd assume. The compressor stays on but i do notice it has a very aggressive start once i turn the air on but i'm not sure if thats normal for cherokees or if thats a signal of the problem.

Rambler65

You need a full gauge set to diagnose what's going on. The cheap low-side-only gauge on those bottles are not good enough, you need to see what the high side of the AC system is doing. (I hope that "AC Pro" recharge bottle didn't have sealer in it, that can plug up the system and cause all kinds of problems.)

Also it's not enough to get the pressure out if what you mean is just having the system discharged (that's kind of what it sounds like), you have to pull vacuum on the system for 30 minutes or more to get all the air and moisture out. If there was air in the system when you recharged it, it's not going to work. You also should have installed a new receiver/drier and put in some additional oil to replace what was lost when replacing components.