The AC in my Jeep never really has worked great since I bought it. I put some gauges on it today. Result: With system off, low pressure. Around 10psi, both Low and High side. Makes sense when pressure would equalize.
Run the AC, Jeep running, gauges read approx 110psi on BOTH high and low side. Since had high pressure, means compressor is compressing. Can be the valves in the compressor are not closing, but I would expect much lower pressure.
But something is not allowing the full AC cycle where thru the evaporator and the metering valve, it does not drop pressure before entering the compressor.
Do Jeeps have Capillaries or some other expansion valve or what? I can evacuate the system and recharge but something is not working. I do get on and off again cooling at low fan speed.

 

Sounds like you could have a bad expansion vavle. Its the rectangular block at the firewall. There are alot of variables in the pressures that you should see. Ambiat air temp. and system load are factors. What was the temp outside? Also, did you have your rpms up? I check my pressures with the engine revs at around 1600-1800 rpm. Where you using quality guages as well?

 

Ok maybe i had a brain fart lol. There are a few different things that could be your problem. Check your condenser and make sure its clean. It could also have a blockage on the inside of it. Even though you clutch is engaging on your comp it could have bad inner seals and not be functioning properly. Expansion valve causing this problem would be rare but it still could be a prpblem. If you are going to recover your system i would go ahead and replace it, along with your accumulator/drier.

 

I was at idle rpms checking it. I do have a belt needing to be tightened. Squealing when take off at a stop with AC on.

I was also thinking Either the condenser has an issue or that expansion valve because I do get higher pressures on both hot and cold sides. Being same hi pressure on both sides of the compressor says that there is compression. And if I turn off the AC for a several seconds, turn it back on, I do get cool air. Not freezing but enough to cool a little on a hot day like it has been. Been around 100 F. So seems that the high side of the compressor is working. It's the low side. Leaves the possible Expansion valve and Condenser problem? Is there a way to check that other than pulling it apart. Checking the outside of the condenser for blockage? It's located behind the Radiator.
As for the Expansion valve, is there a bulb type sensor on it? And where is that attached? Thinking it may be loose?

But whether the valves are closing in the compressor was a question. So if there is pressure generated, then does it means that the compressor is working? I was trying to see if can isolate it. I'll have to recover it and evacuate it. A new accumulator and dryer filter definitely.

 

Your high pressure should be around 210-250...not 110. Your suction pressure is too high and your dishcarge pressure is to low. Sounds like either you have a restriction in the system or your compressor seals are allowing it to leak by. Most of the time a bad expansion valve would have your suction pressure low, and your discharge pressure very high, around 300+. Im not gonna tell you the compressor is bad, but if it where my problem i would go ahead and replace it, along with the accumulator/drier and the exp valve. There is an ebay company with a standard warrenty on their reman compressors called miami cores. A reman'd from them will run you about a $100. I would also pull my condenser coil and clean it, along with blowing it out with compressed air or nitrogen if available. Make sure to clean out your liquid line as well, its the one that looks like it has a small filter built into it. Blow it out from both sides. Then just assemble everything back. Have a good vacuum put on it, charge it up and you should be good to go

 

I'm not holding you to whether it's compressor or not. Since pressures are at same pressures both high and low, then seems that the compressor may not be sealing off completely. I forgot what the R134 Pressures were. Looked them up. At 95F Ambient (Yesterdays temp), Low around 50/55psi. Hi 275/300psi. But since both the same, chances are the Compressor is leaking as you said.
I didn't know what the pressures were so couldn't be sure if maybe just not enough charge. But the low side is higher than should be. And is equal to high side so pointing at the compressor. And that I sometimes get cooling. Well, lucky seal for a few but doesn't last long. I'll be looking at the site for compressors. Need one for my Chevy too. Been dead a long time. Now I want cooling in both!
Thanks,
Any other ideas, I'm open to the help.

 

Just let me know if you have any other questions. I couldnt remember what the pressures where supposed to be off the top of my head as i rarely deal with 134a. Mostly 22 and 404a

 

R22 and R404a. Residential/Industrial Refrigerant Guy.
I took a few courses and know enough about the systems to get by. Man, I should have bought R22 before the government got crazy. Now sky high in full bottles. Something like $1000 where if I bought when I thought about it, was around $130 a bottle.

 

I only do commercial service...no install or change out BS lol. Im getting R22 for about 225 a drum right now. Scheduled to phase out in 2020 i think. I tell you what, if i could only get my hands on some R12.. Lol

 

I didn't think the XJ uses an expansion valve.....it uses an orifice tube instead, no?

 

Pre 1996 use an expansion valve. Im not sure about any newer models. Its the small rectangular metal box at the firewall

 

Gotcha.....ours is a '98, couldn't find any reference to a expansion valve in the '98 FSM.

 

ok thanks. Orfice tube is a little more efficient with a smaller system so i know why they switched. Just wasnt sure if jeep ever did with the xj

 

Mexico for R12. Even though all the bs about being phased out, they still have it. And someone told me they are still producing it.
Yep for smaller system, orifice is good. Just may plug up. I shudder when people buy that sealant Refrigerant. Yep, it seals 'real good'.