I just finished with the almost complete overhaul of my a/c and climate control systems. New hoses, accum, heater and evap cores, liquid line and orifice tube, condenser, blower and resistor, blend and fresh air doors, seals, you get the picture. Since the dash was coming off I wanted to do all that is possible/affordable so I shouldn't need to go back in for a long while.

Now, the air is definitely cool at the vents. In 80 deg F ambient, I initially was getting 60F from the center vent. I went back and told my repair guy this. He suggested cleaning the fins of the condenser. He sprayed them out with water hose and said come back if it didn't make a difference. It didn't so, he evac'd the system and charged it again to be sure. I was there, he brought it back to "full charge" and said he didn't want to risk it by adding more. Later as I drove, I did notice the air was just a bit cooler. It was just below 60, say around 57F. The other tech at the shop says that it all depends on ambient temp, humidity, altitude and a 20 deg drop is typical. I'm at the beach in SC so I'm at sea level.

I've checked other forums; jeepforum, wranglerforum, and others. I see performance charts that show a 43-36F degree drop in temp from 80F should be seen, with around 35psi on the low side, which is what we saw on his machine. Is something wrong here? Is this system just inherently short on performance? Do you think maybe his machine may need calibration? I surely don't want to risk overpressurization but I feel that I should be getting better performance.

Any tips, advice highly appreciated.

ST

 

Most articles I read (before we did our a/c overhaul) said r134a systems were very finicky regarding the correct amount of compressor oil......too much oil, poor cooling performance......too little oil, short lived compressor. We precisely measured/added PAG (oil per the FSM) to the new accumulator and compressor. Buttoned it all up and took it to a pro for vacuum pull and add the correct amount refrigerant by weight. Almost 3 years later, still getting low/mid 30s at the center vents.

 

Here's an Temp/Pressure chart you can reference:



If you are not seeing colder air than expected with a perfectly functioning AC system the blend-air door in the HVAC unit may be allowing hot air to blend with the cool air. As you know from having your HVAC unit blown apart and installing a new blend-air door (?) , the blend-air door system is cable controlled in your '98 XJ and may be out of rig somehow. You might want to inspect the blend-air door crank arm and tension spring installaton, and be certain that the tension band on the bottom of the HVAC unit housing is properly positioned against the cam formation on the blend-air door crank arm.

 

I'm getting the same temps from my vents, and i'm just up the road in Columbia. I've pulled vacuum and recharged (by weight, 20oz) last season and on the best days, it will pull down to 52-53* at the center vent. Pressures on my manifold tester are also in line with where they should be with the ambient temp. I've chalked it up to the fact that my XJ is dark blue, has mediocore insulation, and is, well, a Jeep. It's just not cold as it should be.

I've looked at my blend door, engine cooling system, and any thing i could and it all checks out properly. I usually leave it on MAX AC and just adjust the fan speed.

As compared to my '87 Ranger still running r12.....I can get 36* air from all the vents. I will never change that truck, actually making custom hoses when I swap in my 5.0L.

 

Guess I'll be taking mine in too! Thanks for the informative write up.