I am at a point where I am putting things back together after a complete tear down. So, I am trying to sort out what I should do with my A/C system. First, I have a limited supply of R12 freon but I am thinking I want to save that for my 67 Camaro. I also have a supply of R406a which was a direct replacement for R12. However, I am thinking about converting the 92 Camaro to R134a but concerned with the need for barrier hoses. Does anybody know if the 92 Camaro has barrier hoses or has successfully used R134a without having to recharge it frequently due to migration through the hoses? Additionally, the replacement R4 compressors all say R134a now so wondering if that is only because they come with PAG oil in them for the R134a as opposed to Mineral oil for R12 freon. Does anybody know if you can simply drain and flush the PAG oil from a new compressor and then put in some Mineral oil to go with R12?

 

I recharged my GTA years ago with R134A and did nothing other than use one of those crappy retrofit kits that put adaptors on the Schraeder valves and use ester oil instead of PAG because PAG is not compatible with the residual mineral oil. It wasn't a good way to do it, but it worked OK and needed a top off of 1 can about every 2 years and that went on for about 4 or 5 years until I pulled the motor and opened up the system. I don't think the slow leak had anything to do with the R134A and the hoses since prior to the 134A conversion, I had it charged with R12 and it also lasted about 2 years. R134 was cheap compared to R12, so I just topped it off every now and then and called it a day.

If the A/C system is intact and working, just low on refrigerant, I would just top it off with the R12 you have.

If the A/C system has issues, I would replace everything and use 134A and PAG oil. It sounds like you are replacing the compressor? Replacing the hoses while you are in there is no big deal and at 30+ years old, the old hoses are probably shot anyway. New accumulator and orifice tube are a must and then all that is left is the condenser and evaporator. None of those components are all that expensive, so if you are going to be changing out some of it, just do it all, otherwise you will be chasing issues. Mineral oil and PAG oil don't like each other, and trying to get all of the mineral oil out of the evaporator and condenser is just about impossible. Replacement is a much better bet. Once everything is new, add in the PAG oil, close up the system, pull a vacuum and charge it up with R134A.

 

I thought 90 through 92 cars were 134 from the factory?

 

All thirdgens were R12. R134 didn't start until the 4th gens.

 

It doesn't appear there are any new hoses available. My car seems to be a little rare in the engine compartment (RS/V6) with the battery and A/C compressor the driver's side and requires long hoses to the passenger side. Even a replacement battery tray is only available for the passenger side. Everything I have seen in the way of A/C hoses are shorter and have way different bends for cars with the compressor on the passenger side I guess. I guess I could change it to R134a and if it doesn't work well, go back to R12. I will give Murray Climate Controls a call and see what they say about R12 in there compressors. They likely don't know anything about R406a.

 

Just a thought but you could take your original hoses to a Hydraulic hose shop and have them change out the old R12 rubber to R134a rubber? Don't know if that is cost effective for your needs.

 

Agreed that you should be able to have new hoses made up. A local Parker store can do it.

The compressor should be the same between R12 and R134A, except for the oil. If the compressor comes prefilled with PAG oil, then yeah, getting that PAG oil out of the compressor completely will be tough. If it ships dry, they you should be OK.

Why are you changing the compressor? If it went bad, it likely sent metal particles through system. Most compressor manufacturers require the accumulator and orifice tube to be changed at a minimum to keep the compressor warranty and some also require the condenser to be changed as well, especially if it is a parallel style, which is just about impossible to flush. The OEM condenser is a serpentine flow, which can be flushed. Replacement condensers are parallel flow, which works better with R134A anyway.

Have you pulled out the orifice tube yet? If it's full of metal, assume that metal is throughout the whole system and needs to be addressed.

 

You may want to invest in an AC crimping tool kit. They are under $200 and you can make perfect lines for your application. My local Parker Hanifan stores no longer do AC crimps and before I bought the tools to do it myself I had to bribe the techs at the Thermo King refer unit repair center. The kit has paid for itself and AC fittings are cheap from summit.

 

There was no metal in the system after pulling it apart. It is just that the compressor was sounding a bit funny. I don't want to waste freon if it should go bad right after re-assembly. Anyway, can the rubber hoses be replaced and re-use the existing metal tubes and fittings? I wouldn't think so since they are crimped so that would mean replacing everything. My model has a lot of metal tubing with rubber hoses like the manifold that connects to the back of the compressor.

 

Yes, I did this several years back in a very meticulous manner. Not having any issues with r134a loss. System cools very well too I might add. Still running the same charge from back in 2019 and still cooling great. Its all documented over here. https://www.thirdgen.org/forums/cool...sion-here.html

 

My 91 was and is still R12 from the factory.
My 94 is 134A from the factory.

The 91 has an orifice tube
The 94 has an expansion valve.

If you're changing from R12 to R134a you must change the condenser. They flow differently. I believe R134a uses an axial flow condenser.

If i were switching over, I'd change EVERYTHING. You're looking at no more than about $600 to $650:for all of it.