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Are my thermostats working?

Discussion in 'Boxers/TR/M' started by Jay535, Sep 21, 2021.

  1. Jay535

    Jay535 Karting

    Mar 10, 2011
    74
    Toronto Area, Canada
    Full Name:
    Jay Lebo
    If I go straight from a cold engine onto the freeway and stay there*, temps finally stabilize with water just a hair past the first tick and the oil not yet at the first tick.

    Is that too cold?

    In traffic both oil and coolant get much warmer, but when cruising at speed it seems overcooled.

    Is this a sign that my thermostats are done, or worse, missing?
     
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  3. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    21,627
    Texas
    Full Name:
    Steve Magnusson
    They can't be missing as that would cause the coolant to recirculate in the engine and overheat in traffic. The symptom you describe would be more "one (or both), of the thermostat(s) is(are) stuck in the position that blocks engine recirculation and directs coolant flow to the radiators" -- but I think that unlikely (especially if it all seems to work correctly in traffic). The TR cooling system is really well (over) designed -- here in TX, even if it's 90 deg F outside, the cooling system can drop the temp down to where the radiator fans turn off if the coachwork is moving. What is the ambient temperature when you are going with "a cold engine onto the freeway and stay there"?
     
  4. turbo-joe

    turbo-joe F1 Veteran

    Apr 6, 2008
    7,299
    southwest germany
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    romano schwabel
    that is right, even at my koenig competiton I never get the engine overheatet and also not the engine oil. so really well desinged cooling system :)
     
  5. Jay535

    Jay535 Karting

    Mar 10, 2011
    74
    Toronto Area, Canada
    Full Name:
    Jay Lebo
    Ambient temp is about 65F.

    When I pull onto that freeway, I’m driving very gently because things are still cold, but the rads are getting a 60MPH breeze even with low revs and small throttle openings.

    My car also cools down very quickly when the electric fans come on. They cycle in traffic as they should.
     
  6. ago car nut

    ago car nut F1 Veteran
    Silver Subscribed

    Aug 29, 2008
    5,060
    Madison Ohio
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    David A.
    I had similar experience in my 87TR. On hi-way water temp would go down below normal. Took the thermostats out and tested in water heated on a stove with accurate mercury thermometer. Both thermos opened from close at correct temp, But one would not fully close as water cooled down. Only partially closed. Installed 2 new thermostats, and normal temperature all the time. If you use non factory thermostats, they will work. Make sure you duplicate the small bleed holes of the originals.
     
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  8. barryr

    barryr Karting
    Silver Subscribed Owner

    Oct 16, 2010
    215
    Regina, Canada
    Mine were lazy as well. They would open at about the right temp but would have to be almost cold to close. The affect on the car was sometimes hotter than normal sitting in traffic before the fan would come on and too cold on the highway. Some of the coolant was being recycled through the engine and some is going through the rads.
    I used the matching Volvo ones and drilled the small vent hole
     
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  9. turbo-joe

    turbo-joe F1 Veteran

    Apr 6, 2008
    7,299
    southwest germany
    Full Name:
    romano schwabel
    from BMW also works
     
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  10. Jay535

    Jay535 Karting

    Mar 10, 2011
    74
    Toronto Area, Canada
    Full Name:
    Jay Lebo
    Thanks!!
     

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