Air Pressure Won't Build Over 30lbs N14 Cummins

Discussion in 'Trucks [ Eighteen Wheelers ]' started by Catchley, Jan 19, 2025.

  1. Catchley

    Catchley Bobtail Member

    2
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    Jan 19, 2025
    0
    Hi.
    I have an N14 Cummins engine in Volvo. It won't build air pressure over 30psi. Replaced air governor, adjusted air governor. I drained the air tanks of moisture, poured airline antifreeze down one of the inlets, banged on the air dryer for the purge valve. Tapped on the side of the compressor. Still nothing. This has happened during a rough cold snap in Chicago.
    Does anyone have any suggestions? Can someone direct me to where the unloader valve and the check valve are on this particular motor?
    Thanks.
     
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  3. Heavyd

    Heavyd Road Train Member

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    Feb 4, 2009
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    Air dryer is probably frozen. Banging on it won't help. Disconnect the line going into the dryer and run the engine and see if air is coming through. If so, then bypass the air dryer and see if air pressure comes up.
     
  4. xsetra

    xsetra Road Train Member

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    Aug 21, 2011
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    My n14's had 2 different types of air compressor. The last one I had the unloader valve was on top of the compressor.
    Remove the intake air line from the air compressor. That's where the unloader valve is.
     
  5. Catchley

    Catchley Bobtail Member

    2
    1
    Jan 19, 2025
    0
    Thanks for your suggestions. I'm going to try to work on it Wednesday when the temperature is a little warmer. I'll write back and let everyone know how it goes.
     
    Heavyd Thanks this.
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