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A/C Recharge on 88 Jeep Cherokee

I bought this 88 Cherokee last winter and now that summer is here I want to use the a/c, but of course being that old it needs recharging. A co-worker suggested getting a DIY kit - but I’m concerned now (after purchase! of course) that DIY may turn into SIUY (screw it up yourself).

1- I can’t definitively pin down where the low-side service port is (4L flat 6, btw). Pretty sure that it’s on the firewall but cannot locate. A few web links suggest it has an "L’ on it - dur, can’t see it.

2- This old a car must have been using Freon, everything now is the more environmentally friendly R-134A for replacement. Am I going to have to do any conversion before this recharge?

Seriously considering returning this DIY kit and having my local auto shop graybeard take care of it for me. What do you think?

Tony

Find an air conditioning shop in your area that still uses R-12 (Freon) or at least a general repair shop with equipment and a mechanic old enough to know how to work on your system. Some of these systems had identical ports for the low and high sides. Don’t get talked into a “retro-fit” to R-134, it will never work as well as it would on R-12.

If the system is out of refrigerant then it has a major leak that needs to be repaired first; or the plural of leaks.
The quickest and easiest way to know if there’s a significant leak is to pull a quick 5 minute vacuum on the system and allow it to sit for a bit. Any leak at all will cause the loss of vacuum pretty quickly.
After that then it’s time for a leak check; either with dye and/or a refrigerant sniffer.

Since you obviously don’t know what you are doing, don’t do it… The chances are HIGH it’s going to need more than a re-charge and it’s going to cost more, much more, than the $30 you paid for the kit…

This most likely uses R12, as you suspect. The high and low side ports are the same size. As a quick and dirty test of how bad of a leak it has, you can depress the stem of the Schrader valve on one of the ports with a small screwdriver or similar and see if there’s any pressure in the system. If none or very little, it probably has a bad leak. If there seems to be decent pressure in there, you might be able to get away with recharging it. But you will not be able to buy R12 without a license, and it is expensive. A retrofit kit might be the way to go, but if you have never worked on an A/C system before, it’s best left to a professional.

Any DIY refill kit you buy today is going to be 134a or something other than R12. So the 134a DIY kit you have is not compatible with your R12 system. If you want to consider converting the R12 system to 134a, you are going to need a vacuum pump. If you don’t have access to one, you won’t be able to complete a DIY at home conversion. A gauge set would also be a good idea to have. Under the circumstances you are probably better off taking this to a professional.

Greybeard win! I’ll find a shop to do it. the R12 vs R134A component of the project trumps DIY. Thanks all for your sage advice!

I’ll just disagree a little. I think the cost of repair and refill of R12 is going to be more than converting to 134a. True it will not be as effective and could take you down the road of compressor replacement if not done properly and even if done properly. But once its converted, then recharges are only $100 or so. Seems like once you start on an old system, there’s no stopping until the bill is $1000. Replacing compressors on 134a though and other repairs will be cheaper down the road, and I’ve done new, rebuilt, and new compressors in the past. The lower the cost the higher the risk of failure. Just so you aren’t disappointed when you get a $200 recharge with R12, then face a $1000 parts replacement a while later and having to replace the high cost R12 again. Maybe doesn’t make much sense but I’ve just found long term, seems better to just convert and take your lumps.

That Jeep used an expansion valve that was prone to leak at both gaskets and the condition of the system is a mystery at this point. If, after pulling a vacuum and leaks are found, the system were charged with R-12 and operated long enough to determine if the compressor and expansion valve work, a better estimate could be made on what is needed to repair the AC. Some shops still have the R-12 recovery/recycling machines and usually have sufficient Freon in them to fully charge a system to test them and then recover the refrigerant if needed. That was for years a common procedure for me that could be done for 1 hour of shop labor on most vehicles. Certainly, quite a few Cherokees were checked that way. I do particularly recall that the pre-90 Cherokees had a problem at idle with the engine overheating and the AC pressure going ballistic due to poor air circulation. The cooling system had both a belt driven and electric fan at the radiator but still could not flow enough air when idling in 95*+ temperature to handle the load. Shop around. Hopefully you can find a shop that has the equipment and is willing to check things out.

if you can even find r12 any more you will pay an arm and a leg for it have the system checked over by somebody that knows what they our doing and go from there it will cost less to do a retro fit to your old jeep. uncle sam has taxed the hell out of r12 less you can find some on the black market.

There are legal refrigerants that are compatible with the old R-12 systems. I have used “Freeze-12” to “top off” several R-12 systems with good results. You can find Freeze -12 online…

I had my 81 Camaro converted to R134 back in 95’ish… Right after R12 went off the market in 1994… To this day it still works fine. I have done MANY conversions over the years and have only messed up one…lol Needless to say yes you need a vacuum pump to get all of the old stuff out, this is VERY important. WIth that said, I would bet dollars to dounghts your Jeep was probably converted at some point in its life… The conections are VERY different with the R12 being screw on fittings and the R134 being quick conects you would be able to see if you were converted very quickly.