captain143

Good afternoon, XJ friends!
Have a new issue on my ’92 Laredo and need some insight…
As of about a month ago (just in time for summer) my AC has stopped blowing cold air. It’s definitely not hot or even warm. I would say cool, but no longer COLD.
My first assumption and attempt (after suggestion for a few friends) was to get one of those AC charger canisters from AutoZone. I’ve never had to use one before but it didn’t seem like rocket surgery. After connecting, the gauge just went full into the green, indicating it did not need a charge. Perhaps I was doing something wrong, but don’t think so. That said, I AM still learning…

Would greatly appreciate suggestions on any other things I should consider or should test.

Saudade

I'm going to assume your '92 is charged with R-134a since you can't buy R-12 from the local stores anymore.

Was the jeep running with the AC on max cold when you attempted to charge it? Was the temp control slid all the way over to cold? Use an instant read thermometer in the center dash vent to measure the air temp coming out of the event.

The blend door is operated by a cable connected to the lever. Move it back and forth. You should feel some resistance and possibly hear the door moving. If you look up under the glove box, you'll see the arm connected to the cable. Make sure it's connected.

Check your condenser (in front of the radiator). Make sure it's free from dirt and debris so air can flow freely through it.

awg

Diagnosing A/C faults is quite technical, its one thing most DIY dont even try over here

To diagnose it systematically, you will need to either/both free download the Service Manual. or at least try Google or Youtube for guidance

As you honestly admit to know little on the topic, that will be of invaluable assistance

Rambler65

If that was originally an R12 system has it been converted to R134a? I assume it has the fittings for the newer refrigerant or you would not have been able to hook up the "recharge can". I'm not sure when XJs went over to R134a.

The thing is you really need a full manifold gauge set to diagnose AC problems, with those parts store cans you're only seeing the low side of the system. You have to be really careful working with AC since it's very easy to make things worse or even injure yourself. (Always wear eye protection!) There are plenty of videos on youtube showing how to use a gauge set to diagnose problems. An inexpensive set of gauges (some as low as $30 on Amazon) is fine for home use.

andjones

Automotive AC systems are actually quite simple if you understand the principals of refrigeration (Boyle's Law). I suggest you do you own research on that.

Automotive systems are not sealed systems like your home AC or refrigerator. Automotive systems have many point in which "Freon" (generically used for refrigerant) can leak out. Rubber hoses, gasketed connections and a non-hermetically sealed compressor are all potential places for Freon to leak out. Added to this the vibrations, jostling, temperature extremes and atmospheric changes (changes of altitude) the system receives from a moving vehicle increase the risk of Freon to leak out. Having said all of this, the main failure of automotive AC systems is low refrigerant charge.

Since you have some cooling this fits into a low system charge scenario. When you attached the charge bottle and gauge was the system running? Typically the gauges only give meaningful information when the system is running. Your connection is on the low pressure side of the system as this is the best location to add Freon. When the system is not running the pressure equalizes throughout the system and may give you a false system full indication on your gauge. Refrigeration works based on the different pressures in a properly charged system.

When the system is running does the compressor clutch engage and disengage at fairly fast frequency? This is called short cycling, a common symptom of low refrigerant. Typically the clutch will disengage only after the required temp demand is met (several minutes or more).

I agree with all of the previous posts regarding safety and suggestions.

captain143

Man. You guys are awesome. Love this forum. Thank you for the quick responses.
I definitely followed the guidelines and procedures from the bottle, as I was concerned about safety as well. I understand this is a far different animal from other systems on the Jeep. Always eager to learn, but also smart enough to know when an issue is best left to professionals.
I will get back on it this afternoon and double check the procedure to ensure I didn't miss a step, but I may just run this one in to my local mechanic.

Rambler65

You have to be careful about using those recharge cans. I guess some people get away with using them but they are pretty sketchy and have some serious drawbacks. (For example you can't purge air out of the filler line, can't see high side pressure, and the refrigerant in them may contain sealers that can cause damage.) It's a lot better to use the right tools, basic ones are not very expensive, and better to stick with pure unadulterated refrigerant.