A/C pressures

93ragtop said

I would try misting the condenser with water. If the evap. temp. drops (inside) Then IMO its either overcharged, the condenser is too small, or (and not likely) not getting enough air across the condenser. By it not changing going down the road, pretty much rules that out, again, IMO

If none of that changes, I would suspect a weak compressor.

Click to expand...

Ugh. This must be what it's like to be addicted to something. Ideally, you want a consistant 37* evaporator. IF the metering valve is correctly set (or sized in the event of a non-adjustable metering device ) it shouldn't be hard to achieve. In original Chrysler systems (except A bodies ) there was an Evaporator Pressure Regulator at the inlet of the compressor. This did two jobs - maintaining a nearly perfect evap temp and preventing liquid slugging at low loads. The original system was sized based on a steady flow of liquid at the metering valve inlet. Long story short, change the metering valve (TXV) if you're going to 134a.

I'm not a fan of PAG oil for 134a conversions. I've seen it clump up in commercial systems that were immaculate. Ester oil is readily available at most auto part chains, and is more tolerant of mineral oil traces left in the bottom of the coils, filter-dryer and compressor.