Quiet AC compressor fail?

Bonnewagon

Bonnewagon

Geezer
Sep 18, 2009
5,492
894
113
Queens, NY
#1
My AC quit working just as it is getting hot. I figured on a leak but I have 70psi in the system at rest. Then I checked the fuses and relays and the compressor clutch engages as it should. So the compressor is running but I am getting no change in the high or low side. I am used to compressor failures being noisy and destructive and the system leaking out totally. Is it possible for the compressor to fail internally and not show the usual symptoms and if so what would be the cause? I'm just throwing this out there before I remove it and begin an autopsy and replacement.
 
pontiacgp

pontiacgp

Canadian Prime Minister
Mar 31, 2006
23,480
4,222
113
Kitchener, Ontario
#2
If there is no pressure in the lines should that not cause the compressor to recycle continously?

I came across this, maybe it will help...

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Ribbedroof

Ribbedroof

Royal Smart Person
Jan 4, 2009
2,178
764
113
Wellston, OK
#3
My daughter's Jeep (96 Cherokee) just did this. Worked fine last fall, no cooling this spring. Did an evac and recharge just to make sure we hadn't developed a leak (hadn't).Compressor wasn't noisy, but showed same pressure on both sides. Replaced the expansion valve (relatively inexpensive, and couldn't hurt) with no change, and then installed a new-to-me compressor. Everything is back to normal. 241000 miles, I guess it just wore out.
 
pontiacgp

pontiacgp

Canadian Prime Minister
Mar 31, 2006
23,480
4,222
113
Kitchener, Ontario
#4
My daughter's Jeep (96 Cherokee) just did this. Worked fine last fall, no cooling this spring. Did an evac and recharge just to make sure we hadn't developed a leak (hadn't).Compressor wasn't noisy, but showed same pressure on both sides. Replaced the expansion valve (relatively inexpensive, and couldn't hurt) with no change, and then installed a new-to-me compressor. Everything is back to normal. 241000 miles, I guess it just wore out.
please do not mention a Jeep to Mark, it may cause irreparable distress...:cool:
 
Bonnewagon

Bonnewagon

Geezer
Sep 18, 2009
5,492
894
113
Queens, NY
#5
Brian- same thing. I get 70 psi on both sides even with the compressor running. That is new to me as I have only seen catastrophic failures on other vehicles. My 2000 Cherokee had a noisy failure and I did the compressor, orifice-in-hard-line, hoses, and accumulator. Works great but has a tiny leak somewhere. (Yes Steve- it is still screwing me!). I've had compressors apart and I can't think of anything that would cause it not to make pressure without damage.
 
airboatgreg

airboatgreg

Royal Smart Person
Oct 2, 2016
1,113
700
113
#6
Brian- same thing. I get 70 psi on both sides even with the compressor running. That is new to me as I have only seen catastrophic failures on other vehicles. My 2000 Cherokee had a noisy failure and I did the compressor, orifice-in-hard-line, hoses, and accumulator. Works great but has a tiny leak somewhere. (Yes Steve- it is still screwing me!). I've had compressors apart and I can't think of anything that would cause it not to make pressure without damage.
If the compressor is engaged and you have the same pressure on the hi and low side it is one of 2 things.
1 a bad compressor
2 someone worked on it and left the orifice tube out
 
O

oldsmobile joe

G-Body Guru
Nov 12, 2015
830
522
93
mpls
#7
airboatgreg pretty much nailed it. first you need a compressor to pressurize the high side, and you need a restriction, (orifice) to drop that pressure down. when you say the compressor is running, is it making noise like all r4 compressors do? or is it just spinning the drive plate? most likely the shaft is broken internally, allowing the drive plate to spin but not turning the pistons.
most orifice tubes don't fail. but it is possible. its a quick check to remove the orifice and check its condition and for metal particles.

sorry, man. that sucks.
 
Bonnewagon

Bonnewagon

Geezer
Sep 18, 2009
5,492
894
113
Queens, NY
#8
most likely the shaft is broken internally, allowing the drive plate to spin but not turning the pistons.
OK now that makes sense. I have never had that happen before. The system was never worked on before so nothing was left out or missing. This R12 compressor I got used from a guy on here many years ago. He bought it new but then switched to R134 so he sold it. I changed to ES-12 and even left the original mineral oil in the system. It worked great until just now. I had no idea the shaft could break but that does seem to be the problem. THANKS!!!!
 

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