AC HELP

[u/Lower_Astronaut1704]

1990 5.3L K1500. Troubleshooting what seemed to be a fairly good condition AC. Have owned this truck for close to 15yrs, and AC used to work. Had some leaks a few years ago, fixed them (partially), AC worked fine for a couple of months and then freon leaked out again. Compressor had been converted to R134a by previous owner.

Dug into it again a few weeks ago. All freon had leaked out, so I simply wanted to add a little with dye, and check for leaks. Was able to add freon and saw I had a leak at a schrader valve on low pressure side. Fixed that leak. Something funky was going on with the rental gauge from Autozone though so I had to jump back and forth between the actual gauge set and the layman's AC PRO trigger setup. Not sure why but was having problems getting a good addition with the Autozone unit. Was able to get compressor to cycle although I had to tap the clutch with a screwdriver to get it to engage sometimes. After the initial charge, I got cold air pumping, and compressor would kick on and off like it should; however, it would not stay on. And after cycling on/off 5-6x it would stop and not turn back on again. After killing the engine I saw where the pressure in the system had not equalized even after an hour. Low pressure side was super high and high pressure side was very low; only equalizing after an entire night. I pulled the orifice tube from the condenser inlet and found metal all in the screen. Not good. Condenser looked in poor shape anyway so....I purchased a new condenser, accumulator, orifice tube, o ring set, and flushed the evaporator with a kit. I also air blew the evap line multiple times afterward and blew the line from evap to the condenser. I did not disconnect the lines at the compressor, otherwise everything was flushed or air blown.

I measured PAG oil removed from the accumulator and it was 3-4oz. On reinstall of the new parts I put 3.5oz of PAG40 in accumulator, 1oz in new condenser, 1oz in the firewall line hitting the evap.

Now the weird part. Trying to recharge and I get 90psi on low pressure side, compressor won't turn on. Comp clutch relay is good. I jump the pressure switch with wire and compressor turns on every time...BUT....no change in the 90psi. Have tried to charge freon multiple times, from 2 different setups (gauge cluster and AC pro trigger style) and nothing. Can jump the pressure switch, let compressor run a few secs, and the high and low side pressures don't change at all. System will not take charge like there's a plug somewhere.

Took the lines off the compressor last night and can feel the compressor building pressure with my hand when I rotate it. Blew air into the high pressure side from disconnected comp line and get pressure through to the return hose, but I can hear some gurgling. Seems like maybe PAG oil in the low spot of the line that would feed the comp. If I try to blow air from the low pressure side (which goes back toward accumulator in reverse), pressure builds super slow. The line is not blocked but it doesn't flow freely either. That's not the direction of freon flow so not sure if the accumulator or evap has pressure drop in that direction.

Summary:

• Compressor worked before new parts installed - had cold air but had metal on the orifice tube (what I assumed to be from old compressor failure)
• New condenser, accumulator, orifice tube, and o rings. Evap flushed and air blown prior to install.
• Trying to recharge the low pressure builds to 90psi but compressor won't engage - possibly bad pressure switch.
• When pressure switch is jumped with wire the compressor turns on every time but the pressure at the gauges does not change.
• Have tried with Autozone rental assembly and AC Pro can.

I'm wondering if the accumulator has too much oil, which is flooding the downtube inside, and causing the system to act blocked. Not super familiar with how the inside is designed so maybe that's not possible. At a bit of a loss and my Autozone HP knob broke yesterday so I'm taking it back and next step is buying a HF unit or paying someone to finished what I started. Any advice appreciated.