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So yesterday my brother overfilled my AC by at least half a can after borrowing it. AC was working fine before this but “wasn’t cold enough” for his liking I guess. So he drove it last night and said on his way home the AC started blowing outside temp air. He checked it and discovered it was overfilled so he decided to let pressure out via the high side port (no idea why he didn’t vent it from lowside and I also realize this is illegal as shit) by sticking a screwdriver in. This morning when I go to see what’s upc the compressor will now not engage at all. The clutch does not spin. The AC bottle and gauge I have read at like 10-15 psi when hooked up to low-side, so I figured maybe he let out too much refrigerant and go to add more myself. Immediately upon squeezing the trigger of the AC bottle the pressure now jumps to red-line indicating mechanical malfunction.. When I let go of the trigger the pressure now reads at 35. Evacuating the high pressure side with a screwdriver now makes an air escaping sound but little to no green refrigerant or white smoke comes shooting out like it did last night he says.
What could possibly have caused this malfunction? If it was overfilled wouldn’t letting it back out fix the issue or was draining from high side instead of back out the low what caused an imbalance ? Was the compressor fried from overfilling and driving it a couple hours? Clog in system now? Why does high side AC now seem like it’s completely empty?
Sorry for wall of text. I’m pissed my AC was working fine before and my brother just did a number on this one. Trying to retrace his steps to find out what went wrong.
 

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If you have a twin gauge set, What are the pressures on both sides? This will start to answer your problem. Without them it’s only a guess.
The AC system has both a low pressure cut off switch and a high pressure cut off switch. The pressure must be between these 2 values or the compressor clutch will not get energized.
Crude pressure numbers would be
Low side >35- 40psi
Hi-side < 250-300psi

Find or borrow an AC service manual. You can find good manuals for free on line.
 
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