cbp wrote earlier: "...You should first check system pressure w/o engine running, then when system is operational...."
What should that pressure be?
I checked low-side pressure with a refill kit. The low-side connector is on a vertical tank (accumulator? receiver-drier?).
Engine off, pressure @85F ambient is about 85psi.
With engine idling, A/C on max, the compressor cycles 2 seconds on,
5 seconds off. Initially, pressure varied between about 35psi and 55psi, compressor on/off. Then it seemed to stabilize at 35psi. Checking a while later it was up to a steady 55psi. Checking later still, with fan running in front of the car, it initially cycled between about 25psi and 45psi, compressor on/off, then went again to a steady 55psi. I decided to try a shot of coolant. Adding a shot of coolant would initially shoot pressure up to 65psi, then when the compressor came on it would drop back to 55psi.
also wrote cbp: "and this one for what you should expect to see for system pressures at various ambient temps."
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It sure doesn't appear to be low, but how can it possibly be high if the A/C worked when new? I appreciate the reference, but diagnosis with the chart requires high-side pressure, which I can't measure.thx, nf