A/C issues on 84 C10 with 5.3 LS

[twinturboc10]

On the oil thing - it looks like most Sanden compressors ship with some amount of oil, which is supposedly listed on a sticker. Something to check.

The high pressures point to insufficient heat rejection through the condenser and evaporator or overcharge. That’s why I was curious about line temps. If the condenser can’t get the refrigerant to a liquid it won’t cool. System temps increase and that drives up the pressure.

The displacement of the new compressor is about half that of the old R4, so it will move less refrigerant and heat. A smaller orifice might help. You could try dropping from the OE white 0.072” orifice to a red 0.062” orifice. Dropping from 0.072” to to a blue 0.067” orifice is pretty common with r134a conversions using the OE compressors.