C2 A/C Conversion R12 to R134

[Chris Pergola]

My Original A/C car's A/C unit is out of refrigerant and needs to be recharged.

Given the expense and difficulty of getting and using R12 (not to mention and the environmental impact), I am considering having it converted to R134.

Any drawbacks or recommedations for or against?

Also, would anything be visibly evident for NCRS judging purposes that would result in point deduction if I converted?

Thanks in advance for any advice.

[Roger Coen #30751]

Re: C2 A/C Conversion R12 to R134

I did my 67 3 years ago, no problems.............yet.

Make sure your system is in good shape, change the dryer (different desicant for R134) and use oil that's made for R134a. Above all make sure that you pull a good vacuum, at least 2/3 hr., on the system.

As for visable signs the only one I know of is the fittings for the gas are different so later someone won't use the wrong referigerant. See this site;

http://www.delanet.com/~pparish/retrofit.htm

For lots more info.

rogeroger@hotmail.com

[Don H.]

Re: C2 A/C Conversion R12 to R134

I had 134 in my 65 and have went back to R-12. I experienced about a 4-5 degree drop w/ R-12. As stated, rebuild the dryer and I would recommend the type oil compatible with both refrigerants (I can't remember which, but one is). I use Classic Auto Air of Tampa, FL and am very happy with their service. Don H.

[Larry Gawron]

Re: C2 A/C Conversion R12 to R134

My restoration is almost complete. After reading all I could about R-12 vs R-134 I have decided to stay with R-12. I live in Atlanta, which gets pretty hot and my understanding is that you lose several degrees of output temperature. The C2 & C3 corvettes have a marginal A/C design as it is so I need all the cooling I can get. Also literature on converting states that R-134 puts a strain on the condensor, so it is recommended that you add an additional electric cooling fan for the condensor. There's no room in a corvette for an extra fan. I guess it comes down to how hot it is where you live and how cool you want to be.

[Michael Strinich]

Re: C2 A/C Conversion R12 to R134

Larry,

I've got electric fans on all three of my A/C mid-years. There is plenty of room for a "puller" fan behind the radiator in the shroud. I also run the regular fan and fan clutch for appearance. Most never see the electric pan as it is inside the shroud.

I can't speak for a C-3.

Mike Strinich
#11202

[Pete Whelan]

Re: C2 A/C Conversion R12 to R134

Chris,
I have converted three of my vehicles from R-12 to R-134a with no problems. If your system has discharged, you will need to find the source of the leak and have it repaired. I suspect that the compressor seal is worn, if it hasn't been serviced recently. As others have mentioned, replace the dryer and use ester oil (not PAG). Ester is compatible with the mineral oils used in R-12 systems. Check the expansion valve/orifice too.

If you do decided to convert to R-134a, you will only need about 80% (by weight) of the amount of R-12. I like to keep the low pressure side down to around 35 psi with the compressor running on a 90 degree day. Using air recirculation with the fan speed on high, I've been able to get air outlet temperatures on all three vehicle down to 40 degrees on a 90 degree day.

I have no problem staying cool driving around Texas in the summer and like the convenience of getting cans of R-134a at my local auto parts store. I say go for it. By the way, you don't have to leave the adapter fittings on the A/C lines if you are planning to have the car judged.

Pete