A/C clutch engages, still high low side, low high side

2009 CHEVROLET EQUINOX
100,000 MILES • V6 • 2WD • AUTOMATIC
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BLUEFIRE
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A/C condenser replaced. System recharged after pulling vacuum, which held for 1 hour with no changes. Oil and refrigerant 134a added. System took about 20oz, with low pressure side reading 50 with engine off, high side reads 100. When the engine is running, A/C compressor clutch engages with no noticeable sounds or concerns. Pressure on the low side however, increases to 80, while the high side increases slightly to 105.

Any recommendations on problem? Past history sounds like ac system may not have been running for 2+ years.
Jul 4, 2022 at 12:44 AM
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JACOBANDNICKOLAS
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Hi,

The first thing that comes to mind with those pressures is the compressor itself has failed. When you indicated installing 20 ounces, are you referring to oil? The entire system only holds 4.40 oz. That would cause this to happen. See pic below for capacities.

Let me know.

Joe

See pic below.
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Jul 5, 2022 at 12:12 AM
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BLUEFIRE
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Twenty ounces includes 3 oz of oil only, with the rest being r134a. System previously had an abrupt loss of pressure due to damage to condenser, which has a receiver built into it. My thoughts were a possible bad compressor as well, but since the low side increased when the clutch engaged from 50 to 80, and high side increased a few points, it made me think either a stuck open expansion valve since it sat for 2-3 years empty or a stuck inlet valve on the low side for the compressor. Oil and refrigerant was recovered, system placed under vacuum, and refilled again after sitting for a day. After feeding in oil at 3oz and remaining total volume as r134a to reach 1.3lbs, slowly, compressor clutch engaged and low side pressure dropped down to 30, high side increased up to 200. Current ambient temperature 83 Fahrenheit, humidity 80%, with inner engine bay reading 110 Fahrenheit. After some fiddling, pressure on low side reads between 20-30 with increasing rpm, resting idle 42 approx., high side 230-280. Cabin temperature blowing from 45 Fahrenheit (under load) to 50-54.

Largest concern is when the engine/system is off and equalizes out, both sides sit around 110, in an engine compartment temperature of 100, and unsure if this is slightly too high, due to the low side resting at 110.
Jul 5, 2022 at 4:00 PM
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JACOBANDNICKOLAS
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Hi,

The static pressure seems slightly high. I would have suspected it to rest in the mid 90's based on ambient temperatures.

As far as the low and high side pressures are concerned, they really aren't too far off. Interestingly, the low side is slightly low (42) and the high side is slightly higher than I would have expected, but not too far off.

Since the system sat empty, run it for a couple of days and recheck the pressures to see if there are changes.

Let me know.

Joe
Jul 5, 2022 at 9:31 PM