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Ok, started to talk about this is another thread, but I felt to start my own. So it’s 83F with 47% humidity. Judging by numbers on gauge, low side is low. High is ok. That means bad expansion valve?
Symptoms, it takes roughly 15-20 minutes of driving before you can feel it get cold, once it does, it stays cold. No tinted windows either.
R134 system with 3300cfm e fan.
guys with certifications, what other diagnostics do I need to do? If I throttle any (500ish rpm) high side stays where it’s at and low side drops 15 or more psi.
Last edited by 90project5.0; Jun 5, 2026 at 01:02 PM.
I don't understand this statement. Your idle RPM should be ~650 RPM. Do you mean you ADD another 500 RPM?
Your system does not have an expansion valve, so that is not it. I say it is low on refrigerant. Your high side is still a bit low for R-134a. Is your fan wired to run whenever the AC is on, regardless of engine temp? Do you still have the R-12 condenser in place?
I don't understand this statement. Your idle RPM should be ~650 RPM. Do you mean you ADD another 500 RPM?
Your system does not have an expansion valve, so that is not it. I say it is low on refrigerant. Your high side is still a bit low for R-134a. Is your fan wired to run whenever the AC is on, regardless of engine temp? Do you still have the R-12 condenser in place?
Sorry, an additional 500 rpm’s from my idle of 800. I’m guessing original condensor. Yes, fan controller kicks on with AC signal no matter what.
I will pick up a can. Sorry for the wrong term of expansion valve.
Get 2. They are cheap. You will use it eventually.
You should expect your high side to be a little higher than the chart due to your R12 condenser. R134a needs about 50% more condenser area, so your R12 condenser is not going to cool the refrigerant as well as it should. Remember the old rule of thumb - pressure equals temperature.
Looks like to me the fixed orifice is getting clogged, or it has too much oil in it
I'd evacuate and recharge it and inspect the fixed orifice
They work fine at 150 pounds on the high side and 30 on the low
Your high side is a bit high, and your low side is a bit low
If it was real hot outside of your condenser plugged with debris, those numbers would be normal and I'd add some freon
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