Temperature gauge

Discussion in 'VW Mk3 Jetta, Passat TDI and other/older diesels' started by BOBMATTHEWS, Mar 18, 2017.

  1. BOBMATTHEWS

    BOBMATTHEWS New Member

    Joined:
    May 17, 2013
    Messages:
    21
    Car:
    2005 Passat TDI
    Location:
    Seattle
    My question is simple if the car is running fine but the temp reading on dash is below normal (12 o'clock position)operating position, is that a concern?
    Obviously not overheating, is there such a thing as underheating?
    Would it be the thermostat or the temp sending unit that might be needing replacement. Coolant was low a bit but topped it off and it is staying topped off but no change in not getting to needle on temp dash pointing straight up, a bout to the left.
     
  2. BOBMATTHEWS

    BOBMATTHEWS New Member

    Joined:
    May 17, 2013
    Messages:
    21
    Car:
    2005 Passat TDI
    Location:
    Seattle
    My question is simple if the car is running fine but the temp reading on dash is below normal (12 o'clock position)operating position, is that a concern?
    Obviously not overheating, is there such a thing as underheating?
    Would it be the thermostat or the temp sending unit that might be needing replacement. Coolant was low a bit but topped it off and it is staying topped off but no change in not getting to needle on temp dash pointing straight up, a bout to the left.
     
  3. crsmp5

    crsmp5 Well-Known Member

    Joined:
    Feb 14, 2012
    Messages:
    1,432
    Car:
    85 kubvan
    does engine temp read same as gauge?? the duel sensors fail... throwing one of the 2 off
     
  4. j_martell

    j_martell New Member

    Joined:
    Dec 4, 2014
    Messages:
    6
    Car:
    2006 Jetta GLS TDI Wagon (MK4 BEW A09)
    Location:
    Centre Wellington, Ontario
    The dash gauge is buffered.....

    I run a scangauge II and monitor engine and auto trans temps. The gauge on the dash will show 90*c (190*F, or the 12 o'clock position) when the coolant is 75-95*c.

    Colder motors will burn more fuel per the maps in the ECU, hurting cold weather milage and causing excess soot in the motor/turbo/exhaust...
     
  5. BOBMATTHEWS

    BOBMATTHEWS New Member

    Joined:
    May 17, 2013
    Messages:
    21
    Car:
    2005 Passat TDI
    Location:
    Seattle
    Is it the thermostat that needs replacing. Temperatures here are 45-60 now any way so not too cold.
     
  6. crsmp5

    crsmp5 Well-Known Member

    Joined:
    Feb 14, 2012
    Messages:
    1,432
    Car:
    85 kubvan
    YES IF BOTH ENGINE AND GAUGE READ LOW... no if only one is
     
    BOBMATTHEWS likes this.

Share This Page