Air Conditioning gurus

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Jun 29, 2024 | 02:24 PM

99.5_Superduty

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Tuned

Joined: Aug 2018

Posts: 367

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Air Conditioning gurus

99.5 7.3 diesel truck.

Air conditioning system is ALL original. About two years ago in 105 degree weather was the first time I ever noticed any issues with the air conditioning. I was on a road trip. Stopped at auto parts store got one a can of R134A along with the cheapo gauge and added some refrigerant. All seemed fine until a couple days ago.
I live in an area with numerous 105 degree days and many days over 90. No complaints about the AC last summer.
Yesterday it was 90 degrees, AC was not impressive. Thermometer in center vent = 65 degree temp on max.
I didn't have a chance to hook up gauges until night. It was 70 degrees ambient when I hooked up gauges.
Some readings I saw (digital gauge set):
39/115
34/128
21/135

The low side numbers are not great, but not horrible (except the 21), right?.

All of the high side readings look to be low according to the chart.

I picked up a new orifice tube. I got a variable orifice tube (below 105 degree model). I replaced the orifice tube and vacuumed the system down. It held 660 microns for 30 minutes. I filled it up with 40 oz of R134a.

Here are some photos of the orifice tube that came out. Some debris. I read that these little wheat looking things are the rings from the compressor piston.

These are the current numbers.

Idle and 84 ambient

1200 RPM and 84 ambient

1200 RPM and 85 ambient

1200 RPM 84 degrees ambient

Some frost forming on the lines into and out of the drier.

My low side numbers look low? High side might be a bit low as well.

What about the frost?

Is this all because compressor is going bad?

Do I need a few more ounces of freon?

Is the variable orifice no good? It was a bit longer than the one that came out. It also didn't seat as far in as the original.