I have an 87 XJ that I picked up about 3 years ago and the a/c has never worked. I thought it was still R12 but I looked today and there is a retro sticker for 134a.

I went and bought one of those refill kits with the hose and gauge. (Maybe not the best but I thought it might work). I have a couple questions:

1 - I turned the engine on for 3 minutes like it said but I'm not sure if the compressor was on. The pulley went around but the center of the pulley that's attached to the compressor did not. Is the compressor bad or is there some kind of fuse or something I need to check?

2 - When I checked refrig level with the gauge it didn't move - zero. I thought I'd try to use some of the refrig and see if it kicked on. When I did that, the needle shot into the red zone. What happened? Is there refrig in it or not?

I really don't want to buy a new compressor. Any help or suggestions of anything I'm missing or not getting would be appreciated.

UPDATE: When I started the truck up to go to the store, I had cold/cool air for about 2 minutes. What does this mean?

 

I dont know if the Renix had a pressure switch on the compressor or not. Id be curious if the compressor had adiquite oil, but I doubt it.

If you are gonna replace the compressor, be sure to do the drier as well, then I'd have a shop do the evac&recharge for you, and have the system leak tested.

Personally I'm judt not a fan of the caned refrigerent gig. But I suppose it comes down to how much you want to spend on a truck from 87. Wish i could be more help.

 

There are too many possibilities to cover w/o more info. I am not putting myself out as an expert but the AC system should be approached thoughtfully or you can ruin a system that may be in need of minor service.

I found this write up useful. Once you have more info you can proceed. Better than blindly putting in freon IMO.

https://www.cherokeeforum.com/f51/hv...roblems-37276/

 

Thanks for the link.

 

As a thermo-dynamic professional of many years, I can tell you this. If you were reading "0" on the gauge, that spells "leak". All it takes is money and time to get it right. Or dont spend the money, guess at it and cause major damage. If you felt "cool" or "cold" air for a few seconds, it was either a fluke or you are lucky. Get a budget, evaluate the system as a whole, and make a plan on how you want to approach this. I am in San Antonio, and it is a necessity to have A/C with the summer coming on, as far as I am concerned, and I spent the bucks, granted it wasnt all at once. If interested in my approach and success, let me know! I can gve you a few pointers.....it's not rocket science...It can be done!

 

Leaks in an R12 system retrofitted for 134a are pretty common if the retro wasn't done properly. The 0-rings all need to be changed and often the hoses. R134 molecules are smaller and will seep through some hoses that held R12 just fine.
Unfortunately a lot of the "retrofits" were done by screwing on the adapters, putting a sticker somewhere and charging 'er up.

Most compressors I'm aware of have a low pressure cutout to prevent self-destruction.
I'd add one can of R134 and see if the clutch kicks in. Make SURE the retrofit wasn't done with the adapters backwards (you'd be surprised).....you should be adding to the low pressure side, not the high!

It's normal for the pressure to run into the red for a few moments with a fresh can. I usually adjust the valve to keep it to about 40 pounds max. If you see low side pressure creeping up over 40 psi after the can has been discharging for a half-minute or so, stop. If the A/C isn't working properly at that point, there is a problem that requires more than just a low side gauge to diagnose.