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A/C Problems

1437 Views 11 Replies 6 Participants Last post by  kepalo
We had a couple of warmer days and I noticed my A/C was working intermittently. It works at idle, but any rpm up to 2K and it will start cycling on and off every 5-7sec. At 2k it will stay running longer up to 2 min before it cycles as long as the fan is on high and the A/C is set to max. I put my gauge set on it and found the following. The temp was 70 deg. with low humidity and the truck hadn't been run for several hours. All readings were taken with the A/C set to max, the doors closed and the fan on high.

Static Low 87 High 92
Idle Low 35 High 140
On Low 20 High 160 *the compressor cycles on and off every 5 sec
Off Low 40 High 70 *this is the pressure the system returns to before cycling again

If I leave the A/C on max with the fan on high and stay above 2K the compressor will run for 2 min before getting below 20 and cycling off. If I turn the fan down and keep the rpm the same the low press. will drop below 20 quickly and the compressor will start cycling. Any lower rpm and as soon as the compressor kicks in the press drops within a couple of sec below 20. Any help is appreciated
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HOLD ON !!! I had the same symptom when I bought a truck and turns out it had TOO MUCH Freon in it. Somebody overcharged it trying to solve the above problem. Have it gauged BEFORE you charge it so you don't mess something up. Most of the time this is happening on higher-mileage trucks with the original compressor and clutch with a worn disc. Solution? You can replace the clutch, the compressor and clutch assembly, OR (what I did ) get a little more out of the original by loosening the belt and taking t off the top pulley, move the coolant recovery tank out of the way, remove the small bolt on the a/c clutch center and then the outer clutch assembly. Remove the small spacer washer (about the size of a dime), and possibly use a file or Dremel to remove about the same amount of material from the end of the bolt, then reassemble. Did mine two years ago, and I still have nice cold air. All this does is compensate for wear in the magnetically-attracted clutch disc, and buy maybe another 200 thousand miles before the clutch should be replaced !!!
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Sorry, I didnt see the numbers when I read the OP on my phone. What about a faulty clutch cycling switch or an orifice tube crammed full of something that came apart in there? I'm just guessing from way over here. I used my heat a little this morning...
I'm also skeptical of the over-the-counter stop-leak stuff. I trust the one person that works on my vehicles that does about the only thing I can't ( a/c work since I dont have a way to vacuum, flush, and fill with appropriate amount of oil) when he tells me after 40 years in the business of treating people fairly he never recommends stop-leak. He does use UV dye to find a leak and repair or replace the appropriate part. On my brother's GMC it was a lose Schrader valve, mom's car a leaking o-ring, and on my Ol' Red F-250 it was a leaking accumulator. I used A/C Pro once in a Jeep Cherokee on a drive to Arizona in 100+ heat and put another can in for the return trip...
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