AC not working

[GlennSullivan]

It is always a good day when the simple, least expensive solution solves the problem, even if it is temporary. Keep an eye on the pressures, it prolly has a slow leak.

 

[JamaicaJoe]

I have a 2001 Expy. The AC only gets down to about ~50 to 60 F at the dash. It is 83 F ambient and humid.

Yesterday I bought an ACPRO ACP100V which has a gauge with color coded ranges. I connected it per instructions and the Low side pressure was over 55 or 60 PSI and in the red. (ambient 83F) There are no instructions with the kit to reference the pressure to the ambient temperature leading one to think it is either overcharged or needs service. I belieive the AC clutch was engaged throughout the test. Not sure how to proceed.

 

[Hamfisted]

Joe that's overserviced, a little too much freon in the system. You really need a full gauge set on the system to get it just right. You want the low side 35-40 and at least in the green band on those DIY gauges. The high side pressure switch will kick the compressor off when it's overfilled like that.








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[JamaicaJoe]

Today it is about 82F According to the chart and info below I should see, with the system off, a static pressure of 90.2 PSI. If less that would indicate a low charge, if higher would indicate an over charge. Is this correct?
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UPDATE: I found the static pressure was 105 PSI, however the ambient temp (inside the car) much higher due to the car being in the sun for hours. I did open doors and run the fan a while which lowered it.

Withe the AC compressor running for about 5 minutes at 3/4 fan I got a low side reading of about 35 PSI which is 5 or 10 PSI lower than what it should start to be with the 82 F air temperature. My impression is that the refrigerant is slightly low. But it is cooling and the compressor does not appear to be cycling.

It is tricky testing this because getting the correct temperature readings is elusive to me.
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Static pressure reading

To find the static pressure reading for your car, attach to the hoses and gauge set to the high and low side ports of your AC system.

ricksfreeautorepairadvice.com

 

[Hamfisted]

With a set of gauges. What's your low side, and high side pressures with the AC in the recirculate mode, windows closed, blower(s) on high and the compressor engaged. Not interested in static pressure, other than to say yes, there is some freon in the system before I engage the compressor, to avoid damage.
If you don't have any, you can pick up a set of gauges at Harbor Freight pretty reasonable.




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[GaryH]

@ OP. Yeah, it was just very low on refrigerant. I usually fill until the compressor stops short cycling like that. But without a gauge, you are still just guessing. You can buy a can of R134a that comes with a low pressure side gauge. That helps a lot to see where you are at and keep from over filling, which is bad.