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Air conditioning does not work when hot outside

Old 06-22-2012, 05:43 PM
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Default Air conditioning does not work when hot outside

This is for a 1997 Cherokee.

I recently had my a/c recharged by a shop. It would only blow cold for 3-5 minutes before dying out. The shop tested for leaks and made sure the compressor was working properly. After the recharge, I tested the a/c, and it worked fine. However, I live in a very moderate climate, and a/c is almost never necessary.

But when I was driving through a much hotter part of the country this past week, the a/c did not work at all. Not even a hint of cold air.

The a/c blows very cold when I'm at home, so this is not just a matter of insufficiently cold air.
Old 06-22-2012, 05:56 PM
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Check the condensor fins for debris and damage, a condensor that doesn't properly dissipate heat will cause poor a/c performance especially in hot weather.
Old 06-22-2012, 11:33 PM
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An AC system is a sealed system meaning you don't "use up" freon. If the only thing that was done was a recharge, then it's lost it's charge. You need to have the system leak checked, repaired, put in to a vacuum and then charged. Otherwise, you're just throwing your money out the window on freon.
Old 06-25-2012, 12:09 AM
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Originally Posted by XJcountry
Check the condensor fins for debris and damage, a condensor that doesn't properly dissipate heat will cause poor a/c performance especially in hot weather.
Also make sure you secondary fan is turning on if now the High side pressure jumps up really quick and the a/c clutch will not engauge
Old 06-25-2012, 03:02 PM
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From another forum

Cur and paisted

I had an a/c - radiator shop check it out. Here's the story -- the a/c compressor clutch engages using a magnetic attraction. Over time, the clutch and/or compressor face wear down and the "air gap" between the clutch and compressor face becomes to wide and the magnetic attraction is no longer strong enough to engage or keep engaged the clutch. With mine, the mechanic said it was close enought to engage but after the underhood temp got high enough the natural resistance between the two parts increased and the magnetic attraction couldn't "hold" so the compressor would disengage and produce warm air. Stopping my engine and restarting (which I described in the original post as "fixing the problem") would re-engage the clutch and produce cold air again. The clutch uses shims to increase or decrease this "air gap" and the mechanic simply removed the compressor and removed one shim and adjusted the air gap to the proper distance. Works super now and problem is solved... for only $100 labor on what could have been a multi-hundred-dollar a/c problem. I feel lucky... and cold. Thanks for everyone's input; hopefully this solution will help someone else with the same problem.
Old 06-25-2012, 07:08 PM
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Originally Posted by Saunders
From another forum

Cur and paisted

I had an a/c - radiator shop check it out. Here's the story -- the a/c compressor clutch engages using a magnetic attraction. Over time, the clutch and/or compressor face wear down and the "air gap" between the clutch and compressor face becomes to wide and the magnetic attraction is no longer strong enough to engage or keep engaged the clutch. With mine, the mechanic said it was close enought to engage but after the underhood temp got high enough the natural resistance between the two parts increased and the magnetic attraction couldn't "hold" so the compressor would disengage and produce warm air. Stopping my engine and restarting (which I described in the original post as "fixing the problem") would re-engage the clutch and produce cold air again. The clutch uses shims to increase or decrease this "air gap" and the mechanic simply removed the compressor and removed one shim and adjusted the air gap to the proper distance. Works super now and problem is solved... for only $100 labor on what could have been a multi-hundred-dollar a/c problem. I feel lucky... and cold. Thanks for everyone's input; hopefully this solution will help someone else with the same problem.
I had read about this problem before, but does this apply to 97-01 XJs?
Old 07-21-2012, 01:23 PM
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About a month ago I took out an a/c clutch shim using the procedure described in this thread: http://www.jeepforum.com/forum/f11/a...83/index2.html. In addition to removing one of the three shims I also removed what looked like a spider egg casing that was stuffed into the clutch. I didn't get to test the a/c in the heat until a few days ago, but it blew cold for several hours in 95+ degree heat, so this seems to have fixed my problem.
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