I have a 1966 with an original under dash evaporator on the AC system.
I rebuilt the original Compressor and installed a new dryer, condenser, and expansion valve. I kept the original hoses including the original discharge hose. I vacuum checked the system and then filled it up with r134a.
That was maybe 3 months ago.
Because I hadn't installed the AC solenoid on my Holley Carb, I hadn't tried running the system for a couple of months. When I tried it a week ago, it would never get cold.
I suspected that the r134a probably leaked past the discharge hose since it didn't have the barrier. The thing is the clutch is engaging. I have been told that I should have sufficient pressure if I have a low/high pressure switch in the evaporator.
So, the question is is there a Low/High Pressure Regulator in the original Under Dash Evaporator for a 1966 Ford Mustang?