I'm getting ready to piece the A/C system in my car back together since it is the last thing left on my "Daily Driver Must Have" checklist.

Now I'm going to emphasize here the fact that I will need a new EVERYTHING. The HVAC control panel and the accumulator/compressor wiring is still present but that is IT! I will be replacing (As in currently do not have) the condensor, compressor, accumulator, lines and evaporator (My evap is still present but was mangled badly during my header install).

So far I have the pressure switch that goes into the compressor (Was this the high side switch? Don't remember), and a new orifice tube.

I want to take a second to ask a side question about the condenser/evaporator. Sometimes I see some NICE ones in the junkyard and am tempted. How often do these things spring a leak? Would it be safe to grab a JY unit and have it flushed or would it be better to buy a new one (Cost obviously being higher if new)?

I'm getting ready to purchase an accumulator and compressor package off fleabay:

http://www.ebay.com/itm/130152689084...84.m1436.l2649

Piecing the system together and taking it to be put under a vacuum before charging looks to be common sense. HOWEVER, I am left with a FAT dilemma here. Which refrigerant to use.

Obtaining some R12 would seem to be the EASIEST route but it will cost you an arm and BOTH of your legs. R134a seems to be the most practical approach, as it doesn't require a 609 EPA license to purchase, is readily available just about anywhere and is the current trend. However I am turned off by 134a due to the retrofit complications alot of people seem to be having and the biggest issue being sub-par performance in comparison with other refrigerants.

I was pretty sold on autofrost, until I found out you can't buy it anymore -___-.

In a nutshell, what I am looking for would be something that had equal to or greater than the cooling performance of R12, was a "Direct replacement" for R12 which would eliminate alot of the compatibility issues with retrofits (Which to my understanding comes from types of seals and oils used which can lead to contamination of systems that weren't properly evacuated. Since my system will be a newly built setup, I don't think this issue will apply. Still, high 40 and low 50 temps at the duct don't sound too appealing with R134a), and didn't cost a small fortune. I realize that I would have to get a 609 license to get anything other than R134a and if it means superior cooling, that would be a non issue.

Also, it seems that the stock pressure switches that are calibrated for R12 don't regulate the system as they should with certain other types of refrigerants?

Help me out here guys. This is going to be my first venture with A/C and I'm a complete dumbass at the moment in regards to the subject.

 

Freeze 12 is the replacement for R 12. It is supposed to be a little better actually. It is what I have used and it works great. It also works with the factory R 12 oil and the pressures are the same. I have also used one called hotshot. I think it is 414B and it works great but is more expensive. Different refirgerants require different size condensor and evaporater coils to work at its best. 134 has bigger condensor coil than our old school R 12 cars. So when you change it works and gets cold but engineering wise it is a compromise. I think the oils are different also which means you have to flush the entire system.

 

Well, if you are changing out all those parts, that should eliminate any compatability issues with any old R12 oil in the system. If you find junkyard condenser and evaporator in good shape, just make sure to flush them well. New condensers are cheap enough and easy to find.
If it were mine, I would make the switch to R134a, cheap and easy to get a recharge when the time comes. Just make sure to add PAG oil to the new compressor and follow the service manual recommendations on how much oil the system requires.

 

ABSOLUTELY NO WAY WILL HOTSHOT OR FREEZE 12 cool better than R134a, in fact it will cool WORSE.

If it were me I would be to use a 60/40 mix of R600a/R290a in that proportion, charged roughly 1/3-1/2 of the original system capacity.

 

Did you talk to these people about Autofrost?

http://www.refrigerantsinc.com/contact.html

 

Yes it will cool better than 134a. Take a look at the condensor and evaporator size. Actually they both cool the same but 134a takes a larger condensor making it less effecient. The only reason they changed from r12 was because of the ozone which was a fabricated story so the fed could charge an extra charge. R12 is methane based which is much heavier than air so how can something heavy (atmospheric wise) go miles into the air and hurt the ozone. The things hurting the ozone are;
1. jet air planes
2. Cow flatulation
3. volcanoes

Unless the discovery channel and several articles are wrong.
By the way I am a class A HVAC contractor since 1983 and a general contractor since 2007.