Hello DAVID VITTITOW,
You are very welcome. I am here to help.
Pressure will drop on the low side as RPM increases and high side will go up in pressure. It also depends on the ambient temperature.
If pressure is too low the system's low pressure switch will turn the compressor off.
In Georgia especially if he is in traffic, the A/C won't work as well because there isn't air moving over the heat exchanger/condenser. The cooling fans should help but they can only do so much.
If it gets better driving down the road as opposed to sitting in gear in traffic then this is normal to an extent.
If it is too much of a temperature difference, then getting an A/C machine on it and having it checked and refilled might be a good first step. They will pull a vacuum on it for about 20 minutes and see if there are any leaks.
You can also get a gauge set and check the pressures yourself. I will add an image of them for you.
I am also adding a temperature chart for you. These ranges are approximate values. Keep in mind if you do use gauges to check it, some refrigerant will be lost.
Personally, I would run it for a while and have him keep an eye on it and see if it gets worse.
A good accurate way to measure the temp coming from the vents is with a food thermometer or something similar. He could use this to keep an eye on the temperature. They have ones that clip onto the vent as well.
Hope this helps.
Images (Click to make bigger)
Wednesday, August 2nd, 2023 AT 10:09 AM