2011 Peterbilt 348 engine fan won't shut off.

Discussion in 'Peterbilt Forum' started by Lazer, May 12, 2022.

  1. Lazer

    Lazer Road Train Member

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    2011 model year, PX-8 motor. Engine fan won’t shut off, on full time. Truck is a former BJ Services fleet truck. Have a hunch former owner rigged it somehow to have fan on full time. No noise from fan clutch when turning on ignition, even with full air. No air from fan solenoid on fire wall when pulling off air line to fan clutch, with engine running, and flipping fan switch in cab.
    TIA
     
  2. baha

    baha Road Train Member

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    Ck the switch to be sure it's not the problem and may be sending power to the fan at all positions? You can try to air up the air line going to fan hub and then ck fan for free wheeling?
     
    Last edited: May 12, 2022
  3. SmallPackage

    SmallPackage Road Train Member

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    Is it an electronic viscous clutch? They never do stop turning or freewheel much and are pretty quite.

    Might be BJ put one on or modified the clutches in the air clutch to run full time and left the disabled plumbing and solenoids intact since those trucks just idle all day in the heat with the Ac blowing cold.
     
  4. Lazer

    Lazer Road Train Member

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    Well, thats possible, but this one is not quite, it roars. Going down the road with the windows open, listening to the radio is a lost cause.
     
  5. SmallPackage

    SmallPackage Road Train Member

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    What i meant by quite is the clutch itself. It is not really noticeable by sound when it kicks in fully. Doesn’t add extra sounds or make anything loader then it already is so to speak. Them plastic fan blades are noisy no matter what and I can relate to them driving one crazy running full speed all the time.
    The old school steel bladed air fans were nice. No noise from them. The only way to tell they kicked on was the temp gauge falling and a rush of heat thru the firewall. Lol.
     
  6. Lazer

    Lazer Road Train Member

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    Had time this morning to disconnect the air line from the solenoid, and direct connect to the shop air. Evidently the fan clutch is locked up, could not free spin the fan with or without air pressure. Clutch made no noise when pressurized, or released.