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A/C blowing cold, pump kicking on and off every fifteen seconds 850 1997

posted by  rtparr on  Wed Jul 13 11:31 CST 2005
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last visit: Tue Apr 30 16:15 CST 2013
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My A/C was cold, but I noticed the pump kept clicking on and off every fifteen seconds or so, I charged the system with a can of freon, and that seemed to stop it for a while, but then it started up again after several days. I measured the temperature at full blast--between 38-40F. I put the gauge on it and when the pump clicks on the pressure reads exactly 24, right at the low edge of normal (between the green and blue). When the pump kicks off the pressure rises to 45, right at the edge of the blue/yellow. But no matter what temperature I set the climate control at, I can hear the little relay behind the glove box clicking on and off every fifteen or so seconds. I can also feel the car hesitate ever so slightly when the A/C compressor engages. Is this normal operation for the A/C system? I don't know whether the system was actually low when I put in a whole can or not. On the low side it read into the green before I charged it, but when the pump was not running it would still read almost 45 and then the compressor would kick on, as it does now. Do I have a leak? I don't think my magnetic clutch is going to last at this rate. Dick








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    A/C blowing cold, pump kicking on and off every fifteen seconds 850 1997

    posted by  jthorner on  Fri Jul 15 18:34 CST 2005
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    last visit: Mon Jan 4 04:02 CST 2010
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    24 PSI when the compressor is running is a little on the low side. 850s are notorious for developing leaks in the evaporator, which is said to be a real bear to get to and change out.

    I would try adding a bit more R134a to get the running low side pressure up to 30 psi or so.

    You might find that days, weeks or months later the pressure is drifting back down if you have the $$$$$$$$ leak.

    John







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    A/C blowing cold, pump kicking on and off every fifteen seconds 850 1997

    posted by  someone claiming to be ksg on  Wed Jul 13 12:38 CST 2005 [RELATED]

    Please look at this link -

    http://au.geocities.com/ozbrick850/aircon-keithP.html

    There you will see that the compressor can cycle on and off under 2 conditions -

    either there is not enough gas in the system (so the overall pressure is too low)

    or the air is sufficiently cold in the car and the compressor cycles off to keep the evap from freezing.

    If you are comfortable inside the car it suggests that the latter is the truth.







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