My only experience with R4 compressors was on my own '88 and '94 Suburbans, which were orifice tube in front and expansion valve in the rear. The 1988 was R-12, the 1994 factory R134a.71403 wrote: Unless you dealt with R4's when they were common in daily drivers 15+ years ago you don't appreciate what a headache they were.
Yes, I had to replace the AC compressors in both, and I remember reading that these same R4 compressors lived a lot longer in similar GM trucks that were front-only AC, and the issues were related to the Suburban's dual AC. Even so, the R4 compressors lasted a several years at least, in Arizona and with daily use. So could work fine for poster's application.