View Full Version : A|C General Question
I have just very basic knowledge of the A\C on vehicles. My question is this; What causes to high of pressure on the high side? I still need to get a set of manifold guages for both low and high sides so do not know the pressure reading of the high side. I do have a filler with the guage built in. When I hook that up to check the freon (R134A) it pulls to the bottom of the gauge (I forget the numerical reading). Would the system just be a little low, or have other problems?
When I run the A/C for more than a half hour, it makes the truck run rough, (spit sputter strain to go), temp gauge rises a little higher than normal, but stays to the left, like on the gauge say NORMAL, needle points around at the O and R. Would Evacuating the system and pumping it down over night then re fill do any good?
Excessive high side pressures are usually caused by a blocked orifice tube. Evacuating and refilling will not fix that. Neither will replacing the orifice tube; you have to figure out what blocked it. Hope it isn't metallic (it's likely your compressor if it is).
Well the puzzle is the former owner spent $500 fixing the a\c, New Compressor installed, pumped and filled. I do not know the High side readings yet. Just the low side, but it reads well below the Blue line (this gauge has Blue, Yellow and Red; Blue=Full, Yellow=caution and Red=Danger).
Was just wandering about it, not really worried about it now, but later on I will look into it. Would like to understand more of the A\C System first though.
Autozone has a DVD on A/C's, maybe I will buy that first.
Thanks Makg, I bought the DVD on how to air conditioners. That was very informative. Takes you through step by step, and you were right, even though the former owner replaced the compressor (probably junkyard), still could be it. But also learned that the Dryer should not be exposed very long to the Atmosphere, who knows? Maybe he did not flush the rest of the system, or replace the orfice tube as well, and it is still blocked? Pump for 30 minutes, close manifold gauge valves for 30 min to test for leaks and pull out any unwanted moisture\air.
Man the possibilities go on, won't be able to do much until I get a set of R134A Manifold Gauges though, I have R-12 Manifold gauges, but useless now. Oh well, has not been real hot lately, still have time to get the gauges, have the system purged, then start inspecting\flushing\replacing as needed, I live in florida and will not live without that A/C!!
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