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2017 Prius Coolant Change

Discussion in 'Gen 4 Prius Main Forum' started by Shujayet, Aug 10, 2022.

  1. Shujayet

    Shujayet New Member

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    Hello,
    I just changed my 2017 Prius’ hybrid inverter and engine coolant. In the engine coolant, there is a portion(see the attached photos & look for the cicrled area) it is empty. Although the coolant is on full mark, that small area is empty. Is it normal or should I open that tuny plug and fill it up?
    Thank you!
     

    Attached Files:

  2. CooCooCaChoo

    CooCooCaChoo Active Member

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    It is the same for the coolant overflow tank for the radiator. I think it is normal. As long as it still reads in between low and full, you'll be fine.
     
  3. Shujayet

    Shujayet New Member

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    Okay.
    Thank you. It reads a bit higher than FULL for both the engine and hybrid system coolant tanks.
     
  4. Jburner

    Jburner Member

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    Need to read between low and full (high). There needs to be room in the tank for expansion of the fluid when it heats up.
     
  5. douglasjre

    douglasjre Senior Member

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    What is there need to be room on the top for expansion when there's an overflow port
     
  6. Jburner

    Jburner Member

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    Because when the fluid shrinks after cooling, you would have less in the reservoir if they didn’t have the expansion area inside the sealed tank. And because that’s how they manufactured it, I guess. :)
     
    #6 Jburner, Aug 11, 2022
    Last edited: Aug 11, 2022
  7. Shujayet

    Shujayet New Member

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    Should I get rid of that little bit excess coolant and let it be?
     
  8. Jburner

    Jburner Member

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    Just leave it. I will be fine. It will either be expelled via the overflow or you'll just have extra. Won't hurt anything.