I am working on a 2003 Silverado 2500HD Duramax for my brother-in-law. The AC hose from the compressor over to the evaporator sitting on top of the alternator blew a hole right at the joint of rubber/metal by the compressor. I replaced the line, the accumulator/dryer, and the orifice tube. I pulled a vacuum but my cheap gauges kept allowing them to leak down. I pulled a vacuum and put a can of oil charge on it. Got part of the can in and then nothing. Today I got loaner gauges from the part store and put them on the truck. Both sides showing about 10 or so PSI as they should be equal with no pressure. I put a can of freon, got about 1/2 in and the compressor kicks on. Low side sat about 25ish for a few moments and then when I looked again it sitting at 60 and finally got up to 70psi with the high side only 110 if that. If I turn the system off, the low side goes up to around 110 and the high side comes down a little (they balance out again). The system won’t take any more freon and the gauge is indicating it shouldn’t need any more on the low side reading, so what gives? What am I missing?
An A/C professional.
Been about 28 years, but that used to be me back when it was still R12. I Finally got a complete can in, low side reading 85 PSI, high side little under 150. High side line hot, low side cool but no where near cold. Turn system off, system balances out nearly. I emptied the lines, pulled the orifice tube which is clear, so I am hypothesizing possibly a bad compressor?
It sounds to me like the compressor isn’t pumping correctly. [Edit to add: based upon the most recent post, which I just noticed, there might be air or other non-condensibles in the system, which is why it was difficult to add refrigerant. If the system was correctly evacuated, and non-condensibles are not an issue, then the compressor is defective.]
It should be possible to weigh in most of the factory charge without even running the compressor. (And of course, when charging any type of refrigeration system, if the compressor is off, you can charge liquid refrigerant into both the high and low sides, however if the compressor is running, you must charge the refrigerant very slowly into the low side to avoid ruining the compressor.)
I suspect that you added the liquid refrigerant and oil too quickly, into the low side, and the compressor is now ruined. You will need to start over with a new compressor, new hose(s) and O-ring set, new accumulator/dryer, and new orifice tube.
Make sure to blow through the evaporator and condenser with compressed nitrogen (do not use air from an air compressor). If there is any debris in the system, you must replace the condenser, and that is also a warranty requirement to have a warranty on a new compressor (though I wouldn’t bother, and thus give up the warranty if I’m replacing a compressor that failed mechanically, but didn’t release debris).
What was the operating condition of the vehicle when you recharged it?
And, did you purge the air out of the hose between the low side connector and the oil/refrigerant can before opening the low side valve on the gauge set?
Tester
I did make sure the lines were purged when pulling a vacuum. The system just did not want to take the freon, took it fine and then it was like feeding a baby that’s full, it would take it, but at it’s own pace. The truck was running and of course, no compressor due to no pressure. As the freon was introduced, the compressor kicked in as pressure activated the switches. The low side line was cool, but no where near cold. The high side was hot coming off the compressor. The old orifice tube was awfully dirty. I would say it would be safe to guess the compressor was failing and the orifice tube did its job. A grey mess for sure. The system would equalize when turned off, but the low side always ran high when running and shot up when off to equalize in the system. I tried another gauge to verify it wasn’t a bad reading and both showed about 85 PSI running. I really think the baffles failed in the compressor or are failing which caused a blocked orifice tube and the blow out in the original line. But, as I said earlier, it’s been almost 25 year or better since I did AC work for a living.
The AC system needs to be rebuilt.
That’s debris from a failing compressor.
Tester
I was thinking the compressor was failing. I am looking for the replacement as we speak.
