Hi all, I just did a retrofit on my 91 Firebird. My compressor died and this is what I did.
Flushed the evaporator and condensor Put in a new compressor (harrison), new accumlator, o-rings, and a variable orifice tube. Added 8oz of POE to various components, pulled a vacuum for 3 hours and held overnight.
The high side guage on the borrowed manifold set was broken, so I only have low side readings. system uses 2.25 lb or R-12, So I figured 28 oz or R134a. After adding two cans (24 ozs total). The low side pressure was 31. The duct temperature was 50degF. Ambient temp was 95deg in a garage in humid south florida. With the system off, pressure was 75. With the blower motor on high, a/c clutch would not cycle. accumulator was sweating, high side line just before orifice tube was very warm but not real hot. Am I undercharged? should I add another 4 oz. or leave it alone? Will it cause damage by being undercharged?