R12 vs 134a

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volaredon

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This isn't about an a body but very well could be.
Adding factory AC to my 85 truck, have most of the under dash parts from a junker. I plan to rebuild the plenum box before I put it in.
I don't know if something like this exists but is there any difference between evaporator used with different types of freon?
Same q applying to the receiver drier. And condenser.
PS////still looking for AC compressor mount brackets for a /6
 
You’re going to want to use a new filter/drier but the condenser and evaporator will work either way. Just make sure it’s all cleaned and use the proper oil and 134 seals/gaskets
 
Having done conversions, the above is correct. Get your components together, and there is a spray type cleaner / flush you should use to clean the insides of all the components with. It evaporates quickly as well. When I did it, the cleaner came from the HVAC parts supplier (a specialty shop for radiators and A/C related parts).
 
I added factory ac on my 69 cuda. I bought a new dryer & expansion valve on eBay. Dumped the oil out of the compressor & put new oil in. I put it all together & let it pump down overnight on the vacuum pump. I had a leak or two to find. Charged it with R134 and it works great.

Buy one of those $25 Freon leak detectors on Amazon & go to town!
 
All good advice above. Use a light oil, especially on any aluminum threads. Use new o rings on any connections that have them. Ester oil is compatible with the old mineral oil and 134a, it's commonly available at auto parts stores. You should not try to use a used dryer, the desiccant can be full of moisture.
 
You guys aren't getting what I meant.
As far as evap and condenser I was wondering if they changed things like fins per inch, spacing between tubes etc
and in the drier... I was wondering if they changed the whatever in the bag within for the different types of freon. I think I have the basic how to figured out/ but right now, I know that I have some parts left to locate/ like mount brackets and such. and maybe a dash out of a 80s truck that had factory AC to begin with. (Preferably marroon)
I think I got a guy that I can get the dash from, just need to make the drive up there if he hasn't sold it yet. Just asking these sort of questions while I'm in the parts gathering phase/ so I make sure I get the right ones.
I do have enough R12 stockpiled to run it on but once that's gone where do I get more? So I'm setting it up by for 134 from the get go.
 
volaredon said:
You guys aren't getting what I meant.
As far as evap and condenser I was wondering if they changed things like fins per inch, spacing between tubes etc
Click to expand...

Engineering between the two will be close enough. Changing from one type of refrigerant to any other always requires the proper metering device for the refrigerant i.e. TXV at the head of the evaporator. Also, never reuse a dryer, get a similar sized new one. If you find the flushing solution expensive, remember, it's pretty much just Acetone anyway . HTH, Lefty71
 
It will work, R134A will prob blow about 8° to 10° warmer than R12.
That's just the environmental friendly truth.
 
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Joey4speed said:
It will work, R134A will prob blow about 8° to 10° warmer than R12.
Click to expand...

Wha!!?? That's BS!! Lets see, boiling point of R134....-15degress. Boiling point or R12....-22degrees. Hmm, guess that checks out, carry on lol. :poke:
 
All depends on how picky you want to be. You can spend a few hundred or a few thousand. Probably 10s of thousands of cars on the road where they just dumped R134 in them and called it good. Probably a lesser number done with more care. If all your hoses and components are good, you should be good to go either way.
 
67Dart273 said:
I was under the impression that "things being equal" R12 was a more efficient refrigerant than R134A, but this paper seems to suggest otherwise ESPECIALLY if optimized oils are used with the systems

https://www.aivc.org/sites/default/files/airbase_5960.pdf
Click to expand...

Really interesting. I never knew the reason for different oils. So it looks like if you just dump R134 in it works, but if you change the oil it works a lot better. I usually avoid articles with enthalpy & isentropic in them…..haha.
 
To answer your question, yes pretty much EVERYTHING is engineered/designed differently between the two systems. I went to many tech seminars when the change over actually happened. I distinctly remember them emphasising how the condensers were quite different in the ways you indicate. Now, having said that, I have almost never changed them during a retrofit. The slight loss in performance never compared to the cost of replacement. Same with the hoses, heard all the horror stories about how 134a was going to escape through them very quickly. Never really happened. To me the most important thing was just getting correct capacity. Usually around 85%. BTW, Chrysler's were always the worst performers of retrofits, but I'm mainly talking about late 70's-.80's vehicles. If we were doing a retrofit and the original condenser was bad, we would always buy a 134a compatible unit.
 
yeah I went to a few of those but 1. those were like what 25 years ago? "CRS" happening.
\and 2. Since then the places I have worked are places that didn't offer AC to their customers. I now work at a place where I'm doing more AC work again but R12 never even comes up.... I see a few that specify this 1234 YF but I haven't worked on one of those systems yet.
Will retrofits begin to skip 134 and start going to this crap? I know nothing about this newest freon.
 
When they went to R134 they change the desiccant in the dryers/accumulators. But I can't remember the numbers for it. Any modern manufactured dryer/accumulators would have this already.
 
I will add one thing. I like to replace the factory condenser with a new style parallel flow condenser. However, I'm in florida, and you'r up north, so not as important.
 
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