Freightliner Century Heater Valve

Discussion in 'Trucks [ Eighteen Wheelers ]' started by mrbamcclain, Nov 5, 2012.

  1. mrbamcclain

    mrbamcclain Light Load Member

    Messages:
    160
    Thanks Received:
    60
    Joined:
    May 25, 2011
    Location:
    Hammond, La
    I have a '98 Century with an N-14. I'm not getting any heat to the front of the cab. I opened the valve and the sleeper has heat. Am I missing another valve somewhere?
     
  2. ralph

    ralph Road Train Member

    Messages:
    1,118
    Thanks Received:
    625
    Joined:
    Mar 1, 2009
    Location:
    At The Key Board
    Trace your heater hoses from your heater core/box for the cab from the firewall back to the engine. Is one hot and the other cold?
     
  3. mrbamcclain

    mrbamcclain Light Load Member

    Messages:
    160
    Thanks Received:
    60
    Joined:
    May 25, 2011
    Location:
    Hammond, La
    I only see one valve in the lines
     
  4. ralph

    ralph Road Train Member

    Messages:
    1,118
    Thanks Received:
    625
    Joined:
    Mar 1, 2009
    Location:
    At The Key Board
    Is your coolant level up? Basic question I know but if your level is low there won't be the volume to push the coolant UP to the heater box/core, especially at an idle. Have you tried moving the cab control back and forth a few times? Problems like this are common this time of year the first time we need heat.
     
  5. mrbamcclain

    mrbamcclain Light Load Member

    Messages:
    160
    Thanks Received:
    60
    Joined:
    May 25, 2011
    Location:
    Hammond, La
    Yes, coolant level is in the normal range. I've tried the control but nothing helps. Would there happen to be a vacuum operated blend door behind the dash like in my four wheeler?
     
  6. ralph

    ralph Road Train Member

    Messages:
    1,118
    Thanks Received:
    625
    Joined:
    Mar 1, 2009
    Location:
    At The Key Board
    Vacuum/air operated possibly. Where is your other switch set? Fresh or recirculate?

    Is ONE coolant line warm and the other cold? Is coolant getting to the heater box/core?
     
  7. mrbamcclain

    mrbamcclain Light Load Member

    Messages:
    160
    Thanks Received:
    60
    Joined:
    May 25, 2011
    Location:
    Hammond, La
    I've tried it set to recirculate and fresh. Both lines feel warm to the touch. Neither too hot to hold a hand on.
     
  8. JohnP3

    JohnP3 Road Train Member

    Messages:
    1,594
    Thanks Received:
    618
    Joined:
    Feb 21, 2010
    Location:
    Rock Creek B.C. Canada
    The coolant does not have a flow control valve it regulates the preasure with the blend door of the heater. It is posible you heater core is plugged, especially if you do not have a water filter.
    The blend doors are air operated same as the vacuum ones, only backwards, cars have vacuum trucks have air. If you move the levers you can hear the doors change position same as the temperature control, I do not remember where the valve is but if you shut the truck off, and move the value you should hear it move, or leak. Laying on the passenger floor you should be able to see the doors move all except the defrost, it is under the dash.
     
  9. mrbamcclain

    mrbamcclain Light Load Member

    Messages:
    160
    Thanks Received:
    60
    Joined:
    May 25, 2011
    Location:
    Hammond, La
    How would I check to see if the heater core is plugged?
     
  10. JohnP3

    JohnP3 Road Train Member

    Messages:
    1,594
    Thanks Received:
    618
    Joined:
    Feb 21, 2010
    Location:
    Rock Creek B.C. Canada
    First off have you added any stop leak? If yes it is plugged.
    Second do you have a coolant filter? If no it is plugged.
    Third do you use DCA4? If yes it is more likely to be plugged
    Then run the heater at full temp heat, full fan, be sure the filter is clean, and measure the coolant temperature at the J block outlet it should be a maximum 10 degrees less than the inlet temp with the engine at 1200 RPM.
     
Draft saved Draft deleted