A/C question....help!!!!

Jun 09, 2004 4 Replies
K
95' K2500 w/350CI


When I turn on the a/c the compressor cycles for a few seconds then shuts off for a few and back on again for a few etc. I originally thought I was low on R-134 and bought a refill can that came with a guage. The guage toggles between low (less than 25psi and filled (25-45 psi) depending if the compressor is on or off (again it cycles every few seconds). Sounds to me like a compressor problem, but could this be because I'm low on R-134?


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W

Odds are you are low on refridgerent.

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M

The Input and output lines to the evaporator (inside by heater core) should be the same temperature when the system is full. An inbalance would indicate low charge. This is easy enough to check under the hood.

Cheers

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"

The low side pressure will increase when the compressor shuts off, this is normal. The low pressure cutoff switch will kick off the clutch at 25psi. So, she's hitting 25psi, shutting off, the pressure increases then it kicks back on again.

You need to read the pressures at cruising RPM (in your case likely 2,000 RPM) with the compressor clutch jumped directly to the battery to keep it sucking from the refill can. When you get to 27-30 psi @ 2k RPM, unjump the clutch and it'll stay on, and give you low side pressures around 45psi.

Doc

>
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M

Just FYI. but a great resource for AC info is Ackits.com

they have a great forum that has helped me tremendously in the past.

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