After reading up on A/C retro fitting, I am wondering if it would be easier to just pull the entire R12 system out of my 1990 XJ and swap in a R134a system from a 1996 or newer XJ. It seems to me it should be a bolt in swap if you have all the components. I'm sure there may be the usual issues like having to drill holes etc., but would be pretty straight forward for a seasoned DIYer. Any dialogue would be appreciated! Thanks!

 

A 94-96 system would be more of a bolt in thing, the 97 and newer are way different from your 90 XJ.

 

Wow. Huge project. Just convert it. That's like going in for brain surgery cuz you have a headache.

 

Presuming your r12 system components r good, I'd think it would be way easier to use the old good stuff and convert to r134a. All components must be cleaned thoroughly of old oil and refrigerant and new oil (PAG) that's compatible with r134a installed. There's lots of reading out there on "how to convert". I've converted 2 r12 systems (not XJs) to r134a, both with excellent results (mid to upper 30s at the center vents).

 

Convertings the easiest way, if system work now freeze 12 can be used top it off.

 

Alot of the parts till 93 will work...it just depends how comfortable you are with A/C stuff? but Try and keep as much of the R-12 system as possible. The chrysler R-134 system itself is way different.

 

Hey Bustedback, we used to be neighbors! Born n raised in Sacramento! Moved to Pa. 20 yrs ago. with job. (Base closure) Anyway, so a system swap in your opinion would'nt be brain surgery as some have said? Just bought this rusty old relic XJ and the a/c looks like it was thru a war! My son's 96 is very similar appearing with just different component layout. A complete, good known working system that uses the new 134a seems like a better route to go than try trying to re-hab an old rusted out R12 system. What would be the hardest part about it, besides busted knuckles, toil and sweat? Seems like it would be cheaper too, depending how much you pay for the parts! Thanks for any help!

 

I grew up in Stockton, so we were almost neighbors for sure. If I could see a 90 and a 94 side by side it would take a lot of the guess work out of it. The evaporator will be the hardest part to change out, it requires the dash to be pulled. You can flush the bejesus out of it and save some time and coin.

 

first thing to do would be to put some pressure in it and see where it is leaking if its just a fitting or a hose way easier to replace that. than run power to a/c clutch see if compressor engages if so youre halfway there.
when i did the 134 conversion i didnt do anything but put whatever came in the kit in didnt drain any oil and it lasted for years (not on an xj)