97 tdi running hot

Discussion in 'VW Mk3 Jetta, Passat TDI and other/older diesels' started by 97tdi, May 1, 2012.

  1. 97tdi

    97tdi New Member

    Joined:
    Dec 18, 2011
    Messages:
    14
    Car:
    97 passat tdi
    my car is running hot
    i have replaced the thermostat, radiator cap and water pump once already
    i am using green anti freeze dealership said it was ok because it was an older tdi
    how can i test to see if the water pump is bad other than noticing a leak.
    car runs smooth throughout acceleration and idles fine. the car does not miss and i dont see any steam coming out of the tailpipe
    so i dont think the head gasket is leaking or cracked.
    the coolant fans are working normally as they should. radiator is not leaking and isnt clogged
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  2. chittychittybangbang

    chittychittybangbang Administrator

    Joined:
    May 23, 2007
    Messages:
    21,754
    Car:
    2006 Jetta TDI
    Location:
    CT
    If you drained all the old stuff before adding the green anti freeze it'll work. If you mixed them it will sludge and/or foam depending on what's in the coolant.

    If it looks brown it's mixed.

    Also, there is no radiator cap, there is a coolant expansion cap, is that what you mean?
  3. 97tdi

    97tdi New Member

    Joined:
    Dec 18, 2011
    Messages:
    14
    Car:
    97 passat tdi
    yea the coolant was all drained out before adding the green coolant
    yes I was referring to the expansion tank cap
  4. Traildog

    Traildog New Member

    Joined:
    May 30, 2012
    Messages:
    12
    Car:
    06 Jetta TDI (x2 )84 Jetta 81 Rabbit
    You can open the expansion bottle and look inside while the car is running. You should see the flow by the upper hose ( remove the cap before the car gets hot, otherwise you'll get a facefull of coolant! ). Have someone rev the engine while you watch the flow, it should increase w/ RPM. If no flow, you could have an air pocket. With the car off and cool, remove a hose ( upper radiator hose works ) and see iff air comes out, or if it was full of coolant. Another thing I've seen is that the impeller wheel in the water pump is loose on the shaft, and doesn't spin as it should. Only way to check that is remove the T-stat housing and reach in and hold the impeller while turning the pulley.

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