1234yf pressure “sweet spot”

[Wheelerlabs]

My a/c is working, but it doesn’t get very cold and I feel like it should compared to other cars. I bought a can of 1234yf and when I hooked it up the gauge said I was in the low range of the “good” area; about 30 psi of the 25-50 “good” range. I know adding too much is just as bad as not having enough, so if I were to add a little to get me around 35 to 40 psi, will that make it colder? I don’t want to waste $160 if it’s not going to help.

[JohnHere]

Welcome to the Forum. To begin, what year, make, model, and engine size are we discussing?

Today's A/C systems are quite complicated and can't just be "topped up," so to speak, to make them colder.

As far as the correct charge is concerned, there's only one way to determine that: Have the refrigerant recovered by a competent shop. Their machine will report how much R-1234yf comes out in ounces of weight or grams. Only then will you be able to tell whether it's low by comparing that result to the A/C specs for your vehicle.

The charge kits that are widely available can only tell you that "some" refrigerant is in the system, or none if the attached gauge doesn't register any pressure. In addition, many of these kits contain sealer that you never want to add to your system.

Since the system has at least some refrigerant in it, I recommend scanning the entire system now with an electronic refrigerant detector (or have a shop do it) to find the leak(s). After the leak(s) are located, the system recovered, the leak(s) repaired, and the receiver/dryer replaced, then go ahead to evacuating and re-charging the system to the exact specs by weight, with "exact" being very important.