The pressures indicate a reheating or blend door issue. With evaporator pressures in the 21 to 27 psi range that is a very cold evaporator - well below freezing. Even 34 psi is 39f Yet you have 58f vents. Air flow is likely bypassing the evaporator somehow. It is getting cold. Cycling. First, cyclin...

In general the coil current (and the magnetic field) drops as the coil heats up. The only time a coil draws more current when hot is when it expands physically and begins to short turns - connection the windings in parallel and raising the current. But you say you have replaced the clutch coil. And ...

John:

In those years we were still seeing some dealer installed A/C. Factory cars had the TRS 090 scroll compressor, Dealer air had the piston compressor.

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Ok, so it spent a lifetime idling while it racked up 135k miles. The compressor obviously works ok, it may have been replaced once. Fleet vehicles like those can had odd issues. Evaporator full of dog hair used to be common with K9 units. Can you get an inspection camera to the evaporator with the c...

Was this vehicle actually a police car in a previous life?

This vehicle is a perfect example of why we tell people to do the full load test. None of what follows is aimed at you OP: Trying to add even more refrigerant to a troubled system at idle. People will look at every pressure chart they can find on the internet trying to justify the pressures they see...

WooHoo! Cycling on the HPCO NOW it's a party! Unless the condenser is visibly caked with mud, you get to recover it and figure out what the previous owner did. I would recover it, disconnect the liquid line at or near the TXV and place it in a container to catch what comes out... Then disconnect the...

Is the clutch actually engaging?

If so the next stop is the control valve

Bad schrader valve / service connection. Evacuated the hoses and manifold only.

The clue is the "high side 0" The high side is never zero, unless it is not depressing the schrader valve.

The best thing that company could do for the air cooled 911 would be a heat pump, and ditch the OEM heater. I have had several air cooled german cars. 914 ,111, 912, and they all smell like a hot oily engine with the heat on. Or like the chlorinated parts dip you cleaned the heads and cases in. the ...