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I'm in Phoenix and had to use the AC yesterday. The air blows very cold for about 5 - 10 minutes and then goes warm like the compressor has shut off. If I go back to vent or off for about 5 - 10 minutes and turn it on again, its cold again and goes through the same cycle. Any ideas? I'm wondering if its either over or undercharged - probably overcharged and building pressure with use...
It would be more likely that is is low on freon unless you know for sure that it was overcharged. It could be a number of issues but without a set of gages hooked to the AC it would be guessing. BTW: I'm freezing my butt off up here so I might not be too sympathetic j/k
It could also be the compressor clutch going bad. I had one go bad on me last year,with the exact sme symptoms, some say it is rebuildable, but I never could find the rebuild kit so I just ponied up for a new compressor. which in turn means you need a new orifice, and a complete R&R of the coolant charge. the whole bill was around $700.00 and the compressor came with a 2yr warranty.
Looks like the clutch is $122 @ napa online. They sell a bunch of individual parts for the clutch as well. Looks like I'll need to do some troubleshooting. Since the air is cold, I'm betting the coolant level is fine, but I'll start there first. Is there a low and high pressure switch in the system that will shut off the compressure in either condition?
Nice thread on the electrical workings of the AC system. Its on a ranger, but it my help someone. I know what the cycle switch should look like if its working. I bet my system never gets below 23 PSI in use and thats why it doesn't kick on after the first cycle.
todd, I checked my compressor just by looking under the hood and having a buddy cycle the system in the cab. My clutch would engage slowly and I could tell that the magnets in the clutch were disentegrating just by looking at them.
thats about as far as my expertise goes with the a/c
I believe there are both a high-pressure switch as well as a low pressure switch. First thing I'd do is verify your pressures. If those are good, I'd check into the clutch. It's been so long since I've messed with the AC, I forget if the compressors still have the plug on top that cycles the clutch. However, since it takes a few minutes for it to come back to life, it sounds like it may be pressure related. Once the systems shuts down, it takes a little while to equalize. It sounds like once it does, you can run it again. I'm thinking it may be too much refrigerant, which is causing it to eventually reach the high pressure limit. Have you serviced it lately? The hotter it gets outside, the higher the pressure will be on the high side so it may get worse as it warms up out there (if it *is* an overfill situation).
When I converted my old Bronco over to 134, I filled it until the top & bottom evaporator tubes were the same temp by hand. I know, unscientific, but it worked perfectly that way until I sold it...
Joe
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2002 7.3L F250 XLT CrewCab ShortBed 2WD
you can get an el cheapo pressure guage at wally world or probably any car parts place that will give you a pretty decent guesstimation of how high the freon charge is on the LOW side with the compressor running, or even stopped. I think the one at wally's is about 15 bucks. has colors too.
The high side really needs to be checked, too. If you know someone with gauges, that would be the way to go. Otherwise, you could probably go with the "$29.95 A/C Checks" that a lot of the service places offer. I think the full gauge set runs about $100, +/-.
Joe
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2002 7.3L F250 XLT CrewCab ShortBed 2WD
Check the pressures with some guages. If they check o.k. Bypass the low pressure switch temporarly. I've had several go bad on different vehicles. Many would work short periods and quit for no reason.