R134 Conversion

[friskyfrankie]

This is an old thread but it's interesting to see people actually give decent info on the propane and propane/butane mixes. I don't see myself ever using one or the other since I don't see the risk/reward panning out when r12 is still around and not even as expensive as it was years ago. I see the reasoning in 3rd world countries etc. Since I live in one of the hottest regions of the US, prime AC performance is paramount to me but I guess I'm not willing to risk the explosion if I ever get in a front end collision. R134a conversions have never worked for me. even done completely correctly.

I've read about and done many many R12 to R134a conversions and they DO work, when done correctly. That include accounting for perhaps a new condenser and hoses to account for the differences in molecular sizes of the two refrigerants. .

[Arquemann]

This is an old thread but it's interesting to see people actually give decent info on the propane and propane/butane mixes. I don't see myself ever using one or the other since I don't see the risk/reward panning out when r12 is still around and not even as expensive as it was years ago. I see the reasoning in 3rd world countries etc. Since I live in one of the hottest regions of the US, prime AC performance is paramount to me but I guess I'm not willing to risk the explosion if I ever get in a front end collision. R134a conversions have never worked for me. even done completely correctly.

I have my 85 Grand Marquis running 134a with the factory stuff, a new compatible compressor and the service valves of course. Sure it isn't quite as ice cold it was with Isceon 49 (R12 substitute), but it still beats any average modern car hands down. Biggest problem in my opinion is the massive fish bowl that a box panther is, loads of untinted glass and a large interior volume. I have thought of having uv-blocking tint installed, you might benefit from it alot, protecting the interior too.

[sly]

I converted the 88 MGM, the 93 F150 I had for a while, and the 93. No issues with getting cold on any of them. They do work better with a newer condenser for sure, though.

[Alice87]

On r134a and condensers:

Parallel flow condensers seem to help out a lot with the r134a retrofit AC systems I've installed. R12 has yet to be beaten in my experience, but it's close when you have a properly functioning r134a system. I'm keeping an eye out for a drop in parallel flow condenser to replace the tube/fin one that's in my wagon; I'm thinking a 7014143 will drop right in with little modification.

I had an '89 IROC-Z a while back that had been cheaply/poorly converted to r134a. I swapped the tube/fin condenser out for a cheap spectra 7-3231 parallel flow... it made a noticeable improvement in the Texas heat.

Ultimately if I had a functioning r12 system and a good source of r12... I wouldn't bother trying to convert imo. I know nothing about other mixes. Matter of fact I know very little other than basic installs, and many of you could easily school me on AC systems in general. It's an area of automotives that I need to improve on both in tools and knowledge.

-Kyle

[87GrandMarq]

What year did Ford switch condensers? I have oem used 90 town car condenser in my 87 mgm and it worked great but there is a leak so I figure I might as well upgrade while I’m at it. The ac in my 90 mgm isn’t that great during the day. When the ambient temps are in the 80s and up, the discharge temp will be about 60* while stationary but will drop when moving. The condenser and radiator are clean, the fan clutch is new and good and I get quite a bit of condensation but it doesn’t cool like my 87 did when it was fully functional.

[gadget73]

Probably mid 90s when they changed to R134a. 1993 or 94?

Somewhere in there. I have seen replacement box condensers that are parallel flow. They certainly should be better than the old tube and fin type. Its a common upgrade on Fox cars which have even smaller condensers than the Panther. Those usually get SN95 parts. Euro cars tend to have pretty craptastic AC and convert incredibly poorly to R134a. The canned answer on the 80s BMW groups is a Sanden compressor and the biggest parallel flow condenser that can be stuffed behind the grille.


Still got the propane/butane in the Mark VII. I didn't do that specifically with the goal of avoiding R134a, it was done for leak checking purposes. My sniffer will pick up on hydrocarbon refrigerants just fine and the system was dead empty. Thing is I charged it and its not leaking out. Since cold air comes out of the vents I've been mostly not motivated to fool with it.

[87GrandMarq]

Well it looks like I’ll be upgrading here soon. Thanks. I’ll probably swap out the drier too since the system is pretty much empty now too.

[sly]

94. my 93 was the last year of R12

[gadget73]

Drier is supposed to be replaced every time the system is opened.

[drhill]

good info here, AC became a subject of intense study for me when I moved from the coast to the desert 20 years ago. The parallel condenser swap were not as much of a thing back then but I use them now in everything.

r134a conversions with a parallel condensers are good and frankly for most locations in the US, it never gets hot enough to notice the difference between good running r134a conversion and a good running r12 system. the difference between 100 degrees ambient and 120 is significant. Especially with a car that has been sitting in the sun all day. I just happen to live in one of the places where you notice a slight drop in efficiency.

I use r12 with as large of a parallel flow condenser that will fit plus a huge electric fan. Even when I had a good r12 system with a "police" clutch fan it wasn't enough. Heck my 2003 Suburban with clutch fan sucks to drive in the summer heat here. I have to put it in neutral and rev the engine to get the ac cool at stoplights! Maybe I need to move!

[Mainemantom]

In my opinion, When converting to R134, I do the following:
Make sure system is free of freon. There are a couple of ways to do this. One legal, the other not legal. Completely drain the compressor. Recommend flushing the system, If you don't want to, let the compressor drain awhile and rotate by hand.If the existing compressor makes weird noises or grinding sounds, replace it. DO NOT use remain or rebuilt compressors. I never had one last long. Recommend a new drop in unit. Off the top of my head, 8 oz on PAG oil is used. If replacing the compressor with one that is pre oiled, drain and verify the amount. Refill to the proper level. Do your research with oil amount for your application. Replace the Orifice tube with the same color.. Replace the receiver drier, Replace every single O ring at the connections including at the top of the compressor. Use A/C O rings only. Lubricate the O rings with Pag oil before installing. Inspect hoses, condenser(suggest replacing) Change the pressure switch to a R-34 switch. Reassemble, evacuate for at least an hour. I prefer at least two hours. Add the R134 refrigerant. The last one I did took 24 oz. That equals two cans of 10 oz plus 4 oz. How to you get that 4 oz ? It has to be weighed in using a scale. When the compressor starts to cycle, take your sniffer and check all connections for any leaks. Use the thermometer to check for cabin temperature. Acceptable temp should be in the low 40s. You should have a set of manifold gauges and hoses ( get replacement hose O rings. The ones that are included do not last long at all.
There is allot to doing this job right. Don't forget to use goggles and gloves. Freon can freeze your skin. If you do short cuts by not replacing items, it is very possible to have to redo the work. The investment in the proper tools will pay off IF you are doing a few cars.
Consider having the work done at a shop if you are not familiar with A/C work. Compare the cost of shop work vs your work and the cost of proper tools. A shop will have some type of warranty on their work. These are my suggestions. Other people may choose to do things differently and that is fine. Good luck.