Overcharged AC and Now Won't take a Charge (1 Viewer)

[Gannz]

So I'm an idiot and I overcharged the AC system. I was adding Freon unaware that It was overcharging and there were two successive "burps" that came from the compressor area. These burps were short and accompanied by a small cloud of Freon. I hooked up my cheap gauge to the low side and it was in the red. I shut it off and planned to use my buddies recovery machine to remove the excess Freon. When I checked the pressure later in the day it was at zero. I lost almost all the Freon.

My buddy is a residential AC contractor/tech but he has Parkinson's and struggles to diagnose things nowadays. We pumped some nitrogen into the system and his leak detector detected a leak where the lines connect to the compressor. I figured the o-rings blew out from the high pressure and that's what caused the burps and later loss of Freon. He agrees that there is a leak but also thinks the compressor is shot. I pulled the compressor. The o-rings look fine and there is compression/suction when I hold my thumb over the respective ports while turning the clutch by hand. The clutch engages when the engine is running and the AC is on. It turns off when the AC is turned off. It seems to be working but he thinks it's not pumping because the system won't take any Freon.

Does the fact that the system won't take a charge mean the compressor is bad? The only thing I'm seeing online regarding a system not taking a charge is a clog somewhere.

Would a bad leak prevent the system from taking a charge? We put a vacuum pump on it and he said it wouldn't draw down as far as he wanted which seems to confirm the leak.

Any help/input is appreciated and thanks in advance. I don't want to just throw parts at it until it's fixed.

 

[pat1]

Yes, A leak will cause it not to take a charge. If the vacuum pump won't pull it down you're not going to have the suction to pull the charge in. It needs the vacuum to be at least 28inHG. Now if you had a little charge in the system and the compressor would come on,it would pull the charge into the system.

So bottom line you need to fix the leak. Also the compressor could be damaged to the high head pressure from it being over charged. There should be a pop off valve on the compressor that pops open when the pressures get too high(usually 400+) to prevent the compressor from being damaged. Its possible that this pop off valve is leaking.

 

[Gannz]

Thanks, Pat. The relief valve makes perfect sense given the burps. I did consider a relief valve but didn't find anything online confirming a 4th gen v8 4runner had one so I disregarded it. Looking at it again...

Does anyone know the part number for this relief valve? Or, are they a universal thread/part?

Also, looks like the compressor was replaced around 2014...