1st gen RX-7 air conditioning


I am the original owner of a 1984 Mazda RX-7 GS. The factory a/c worked fine with the original R12A refrigerant, but will not hold a charge with R134A. My mechanic says the cooling system is probably inadequate for R134A. Too much pressure builds up and a valve dumps the R134A before the a/c system sustains damage.

There are several alternates to R134A on the net, but my mechanic is not familiar with them, so is reluctant to try one. Has anyone had success recharging a 1st gen RX-7 a/c system? Are there any aftermarket parts available to increase cooling capacity?


Did you ever get a solution anywhere since on one responded? Have same exact issue and my mechanic said same. Our current A/C is windows down ;(


Hi Paul,

I have not, unfortunately, heard from anyone else. My current A/C is still the same as yours. If I ever find a solution, I will post it.



You folks try posting on the RX7club forum? This CAN’T be a unique prob and lots of guys are still running ACs in FBs.
Lack of exposure here might be the issue- no offense to Hagerty



134 has a different temp-pressure curve than R12 and rarely works well with the R12 compressors. Instead of looking for an alternative to R134 in my 3rd Gen. I’m looking for an alternative for R12 and keeping my system as designed.


Does your mechanic know that your supposed to use LESS R134a? You don’t go by the printed weight for R12 when converting those old systems. I’ve converted many systems. Mercedes, Camaros, MGs and Buicks using the original “R12” pump with no mods. I’d start with 70% of the R12 spec and see if it’s cold enough.



I don’t know the answer to your question, but I’ll ask my mechanic and let you know. Thank you for the advice!