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95 zj ac system not working

850 Views 6 Replies 4 Participants Last post by  zjosh93
So i have a 95 zj where the c system is not working. I took it to a shop her they emptied and refilled the system to factory specs.

Before i took it to them the compressor would kick on for about 5-10 seconds then shut off for about 5 seconds, now it turns on for about a half seconds then turns off for 10-15

They then told me that i needed to replace the high side orifice tube as well as the accumulator because of a possible blockage due to my last compressor ceasing up and smoking. They want 900 for it when all said and done so i said hell no and decided to tackle it myself.

the compressor and the high side service valve are the only replaced components so far. I dont know where the high side orifice tube is and i think thats the next thing i will be replacing.

I will include a link to a video of the gauge readings at 90*F
(the low side slowly climbs to 45psi then drops quickly to 25psi when the compressor kicks on for a second, and the high side stays at around 150psi and climbs a little but when the compressor turns)

I really dont know whats wrong my best guess is a clog in the system any thoughts would be much appreciate its getting hot here in Texas. Thank you!
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Sure sounds like clogged orifice tube to me. The orifice tube and the compressor are the gatekeepers between the high and low sides. It's taking 10-15 seconds for a 100 psi pressure differential to force a tiny amount of refrigerant through the orifice and bring the low side up enough to trigger the compressor. Once the compressor kicks on it sucks the low side down in half a second. On my 93 the compressor stays on pretty much constantly in the summer. Which is how it should be. Compressor short cycling is hard on the clutch.

FWIW any time you replace a compressor for mechanical damage (siezed) you pretty much have to replace the orifice tube, the accumulator (drier), and flush the lines. When I sold parts you'd see a lot of people buy just the compressor and then be back in 3 months with a dead compressor again, killed by trash the first one left in the system. Most compressor companies won't warranty a compressor unless you can prove you bought a new orifice tube or expansion valve, drier/accumulator, and a can of flush.
 

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Good point Wingless. On the 4.0 the orifice tube is built into the low side hard line running from the condenser to the evaporator core along the passenger side of the engine compartment. Typically OEMs make the distance from the orifice to the evaporator core short so the gas doesn't heat up and large so the gas has somewhere to expand. Jeep for no good reason made the line narrow and long so it tends to pick up heat. You can make the AC work noticeably better by insulating that line.

https://www.rockauto.com/en/catalog/jeep,1995,grand+cherokee,4.0l+l6,1182103,heat+&+air+conditioning,a/c+refrigerant+hose,6900

RockAuto calls it the liquid line, even though there'd only be liquid in about 3" of that line, but sure. Cheap enough. It will be soft when you get it. Soft enough to bend it straight or make little adjustments here of there. It will eventually work hard as it temperature cycles.
 

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Discussion Starter · #5 ·
Thanks all for the advice so with everything being said I’m planning on replacing the accumulator and the low end line with the orifice tube inside.

Are there any other orifice tubes or lines that i should replace? I know the heater core was replaced about 6-7 years ago and i really want to try to avoid taking apart my dash.

Other than running shop air through the system to “flush it” what are some easy/cheap ways for me to flush it a little better?

Thanks for the responses I need ac in this Texas heat!
 

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"Other than running shop air through the system to “flush it” what are some easy/cheap ways for me to flush it a little better?"

I've seen people talk about flushing their's with a garden hose, and using tubing, a funnel, and a catch bucket, pouring hot soapy water through. If you can rig it up right with tubing, I guess you could manage get it full of hot soapy water and then use compressed air to get a more vigorous flow than by simply pouring it through. Also I've seen people talk about using rubbing alcohol. The thing about a liquid flush is that you need to dry it out completely afterwards. Rubbing alcohol will evaporate quickly especially if you blow air through, whereas with water you would need to blow it out and might have to let it stay open to the atmosphere for a day or so. After opening the system, you need to have it vacuumed down.
 

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Just buy real AC system flush:
https://www.amazon.com/Four-Seasons-69994-Super-Solvent/dp/B004AEQSE4

Most auto parts stores should rent the flush gun kit or at least they used to. The flush is designed to work with AC oil and lift contaminants out of the AC system.

Bad news is that some condensers and evaporators cannot be flushed. I'm not an AC expert. I think our ZJ evaporators can be flushed and the condensers can't be. But I'd defer to anyone with actual data. Or info from the FSM. I'd look but that PDF is on my other computer.
 
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