View Full Version : A/C swap (R12 to R134a)

April 30th, 2012, 12:01
My A/C is inoperative as it is. I have not yet taken it in to be serviced because I don't want to pump it full of R-12 and then find out I'm going to have to change it over to new parts and R-134a after all that (as in it could be leaking).

My plan was to just to have the shop evacuate and flush the R-12 and then take it home, put in a new expansion valve, hoses, accumulator and a re-man compressor with the 134a nipples. Then take it back and hand have them charge it with R-134a

Will this work or am I just pipe dreamin'??

April 30th, 2012, 12:40
Last I checked you need to swap EVERYTHING. Lines, compressor, etc and it got expensive quick. Like 3-400 bucks or so, but wasn't worth it to me at the time. The old r12 compressor won't work with r134.

April 30th, 2012, 12:47
i think you delete the expansion valve and add an orifice tube. the entire system will need a good flush too as the R12 oil does not mix with the r134a. i have yet to look into this but just check out all the parts from a newer jeep and that should give you an idea of what youll need. some (many) orifice tubes are set into the condenser. so you may need to get a newer style one. i am on the fence with doing this to my 89. i had a 30# bottle of R12 and can not find it now. i do have 4 or 5 cans (14oz), so i can do it once. but in the long run, it may be better to do the swap.

April 30th, 2012, 12:50
i figured if he was getting a new / remanufactured comp, he was getting a newer style one. i dont think you can get the old style with R134a fittings.

April 30th, 2012, 13:20
Just have them do a test to see if you can find the leak or leaks.Repair them and then recharge with R12
My R12 is colder than my other jeep with 134a in it.I got my R12 from mexico in 1# cans.They still sale it over there.I am a AC tech by trade.So i can still buy it here but the cost is way to high for it here

April 30th, 2012, 13:40
An R12 compressor WILL work with R134a provided, of course, that it is otherwise functional.

I have personally converted two systems ('85 XJ and '86 Buick) with no changes whatsoever except a professional evacuation and new compressor fittings. My current '93 was converted by the PO in the same manner. We live just north of Houston with an ungodly combination of heat and humidity and the current system has been functioning quite well for about nine years.

I am by no means suggesting that this will work in every case or promoting it as a solution for everyone but I do have to smile when we hear time and again the flat statement that an R12 system will not work with 134a.

April 30th, 2012, 19:30
I've done two r12 to r134a swaps, my 94 Cherokee being one of them. All I've done is hook up a vacuum pump to void the system as best as I can, then refill with 134a. There are readily available adapters for the ports. I've gone 5+ years with my converted XJ with out so much as a hiccup.

There was a lot of worry when conversions were just being started about incompatibility. My reading shows that those worries haven't been born out and all of the changing over of stuff isn't necessarily recommended anymore. At the end of the day, it's your money. If you feel that changing everything out is worth your time and money, who are any of us to talk you out of it?

April 30th, 2012, 19:43
i went to the parts store bought an r134 conersion kit . evaced mine. added the adapters and added the r134.when r134 first came out there was all sorts of stuff saying you had to change the compressor the acumulator/reciever dryer etc. well some one figured out you dont have to.

April 30th, 2012, 19:47
on a side not i used a later aux/a/c radiator fan from a 97. the changed the connector it has more cfm. r134 doesnt as well and has higher preasures so the manufactures have increased the blower motor fans and the radiator fan with higher cfm to make them cool better.

April 30th, 2012, 22:39
I'm gonna be converting my MJ to R134. JP Magazine did an article a while back. I'm going to Trasborg's place in a couple of weeks and he's gonna help me with the conversion.

May 1st, 2012, 01:06
I'm gonna be converting my MJ to R134. JP Magazine did an article a while back. I'm going to Trasborg's place in a couple of weeks and he's gonna help me with the conversion.

Trying to get your rear end back in the magazine?

May 1st, 2012, 11:25
It's my best side. :p

May 1st, 2012, 20:51
Can you get an R12 system serviced at a shop nowadays; or do they only do R134 systems?

May 1st, 2012, 20:55
Yes you can but most shops charge over 100 bucks a pound for r-12. I charge 75 a pound when i have it after i do a leak test

May 1st, 2012, 20:56
How many pounds does it take to service a RENIX R12 system?

May 1st, 2012, 20:59
I would have to look to make sure, but i think it is 2.5.Like i said i would have to look to be sure