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Coolant heat storage tank

Discussion in 'Gen 2 Prius Main Forum' started by confusedcole..., Sep 19, 2024.

  1. confusedcole...

    confusedcole... New Member

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    Does anyone know if the coolant heat storage tank is actually necessary on the gen 2 or if they are just there for cold start? Thanks
     
  2. MAX2

    MAX2 Member

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    Coolant heat storage tank is used to store heat during short parkings.
    During long parkings in the cold season, the coolant in the tank will cool down and it will not be able to heat the cylinder head.
    This is more for self-esteem.
     
  3. Tombukt2

    Tombukt2 Senior Member

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    It doesn't have to be there so what You're trying to eliminate the code the codes usually not for the tank but for the pump next to it or the temperature sensor or it not coming on when it's supposed to so if you remove all of that and join the hoses together you're still going to have the code unless you've got the capability to edit the firmware and do all that computer programming which apparently nobody's been able to do and I don't know 25 years or so so good luck I have a car with this code right now It doesn't mean anything It just tells me that something's not happening with the coolant heat storage system The pump isn't running or the temperature isn't being sensed properly there's a temp sensor on the tank. I just haven't fooled around with it to see what it is doesn't really matter to me It's just a thermos bottle that I carry around with 5 lb or so extra weight in it.
     
  4. highmilesgarage

    highmilesgarage Active Member

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    The previous owner of my 426k miles Prius has this hack. The 3-way coolant valve failed so he disconnected the hoses from the valve by joining/clamping the hose together (bypass the valve) and disabling the pump by removing the relay. The car will still run fine, it's just for efficiency/emissions thing (just like your oxygen sensor needs a heater during startup) You'll get a check engine light if this is not working.
     
    #4 highmilesgarage, Sep 20, 2024
    Last edited: Sep 20, 2024
    blaisep likes this.
  5. ChapmanF

    ChapmanF Senior Member

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    I'm not sure just now where I found figures for how well the thermos held heat, but I remember being surprised at how well. Under certain temperature conditions, anyway, I seem to recall it was supposed to maintain a useful coolant temperature for a couple or three days.
     
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  6. Tombukt2

    Tombukt2 Senior Member

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    I can't ever park the cars long enough for that to happen but I need to look into that I guess with the silver $700 campus car . I do know the pump runs so there's that It comes on when I start the car and I imagine if I put 12 volts to it it'll sit there and run into oblivion so I'm guessing my problem is either the computer that controls the CHS system or the temp sensor's bad I need to test the temp sensor and see if that's the case but other than that the tank is perfect I can feel the water going in warm and coming out warm from the hoses and it's never been hit dented or anything else so I can't imagine anything could be wrong with the tank It's just a double walled aluminum steel thermos whatever there's no glass in it so what could happen to the vessel? Far as I know nothing until you put a big dent in it with an accident. But the code just clears and the car runs with the code and doesn't lose any mileage and all of that so I've just had that back burner this car's been three sheets in the wind for DoorDash and all that now the person driving the car has terminal cancer and it's here for the duration so I can get around to fixing it I can't fix the person so I can fix the car.