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AC pressure question

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by TX Mudder, Aug 11, 2001.

  1. TX Mudder

    TX Mudder 1/2 ton status

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    Ok, this actually has to do with a 97 Chrysler Cirrus, but it's a basic AC question.
    I just replaced the AC compressor and charged it up. I hooked up a pressure guage to the low pressure hose and it is reading between 35 and 54, oscillating between the two every few seconds. Is it supposed to be a CONSTANT pressure or variable like it is doing?
    The guage says 22-44 is a good reading and anything higher will damage the AC compressor.
    Anyone know?
    -- Mike

    <font color=blue> At some point I'll be done building my truck and can actually go wheeling. Until then, I guess sex and alcohol will have to do. [​IMG]
     
  2. RESTORE89

    RESTORE89 1/2 ton status

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    did you pull a vacuum before you charged it up
    if not it will read strange and not cool properly


    It needs a bigger motor.
    what's in it now?
    doen't matter it NEEDS A BIGGER MOTOR
    89 350tbi/700r4h/np208/4.11's
     
  3. WOODYJ

    WOODYJ 1/2 ton status

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    What refrigerant are you using? 134A orR12? If it is R12--look at the R12 scale on your gauges. This represents the temperature that the freon is comming off of the evaporator. You want to go to high idle and check the pressures. You want the temp comming off the coils at 34 or so degres. This way your evaporator will not freeze up. If it is below 32 off the coils it will freeze up and not get any air through the coil. Also if the pressures are fluctuating as bad as you say--the clutch on the compressor is clicking out due to low pressure(not enough freon in system). I saw another post that asked if you evacuated the system before putting the refrigerant--that must be done! You cannot compress air into a liquid state like the freon. That is where you get the cool is when the liquid freon turns back to a gas--sucking the heat out of the air in your car. I hope this helps. I have been doing it a long time!

    k5woody I Don't Understand The Jeep Thing Either!!!
     
  4. TX Mudder

    TX Mudder 1/2 ton status

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    It uses 134-a. My guage says PSI not temp (it's a basic guage, not the whole guage manifold set.)
    I called the AC place and they think I have it overcharged. I checked the compressor and it's not cliking on and off or doing anything funny.
    The guy said to take alittle refridgerant out of the system and he'll properly evacuate and refill it on Monday. I did take some out and it's cooling a little better. We'll see.
    No, I didn't evacuate the system first. All I did was remove the old compressor, put oil in the new compressor and bolt it on. THen I just charged it through the low side. So I know it has air and moisture in it. The guy said $85 to do it it on Monday, so that's what I'm going to do. I'm still money ahead - the shop wanted just under a grand to put on the compressor! It only cost $239 plus $50 worth of 134-a, PAG, and hoses/guage.
    Thanks for all the help!
    -- Mike


    <font color=blue> At some point I'll be done building my truck and can actually go wheeling. Until then, I guess sex and alcohol will have to do. [​IMG]
     

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