Bigger gas tank after heat wave

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by pasadena_commut, Sep 9, 2022.

  1. pasadena_commut

    pasadena_commut Senior Member

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    It has been insanely hot here for far too long, every day over 100F, most over 105F. As usual, fueled it up right after it dropped to one bar on the fuel gauge when it was 104F and it took 9.8 gallons, way more than the previous "record" (for me) of 9.2 gallons. I know that the rubber bladder in the tank is heat sensitive, and should be much softer at these high temperatures. So it didn't surprise me that it took more, although it did surprise me that it was that much more.

    I'm also wondering now what a "hot bladder" does to the fuel gauge measurement. Is 1 bar at 105F the same amount of fuel left in the tank as 1 bar at 45F? I'm guessing that the height of the tank where the gauge is located is constant, and the bladder volume effects are out to the sides. So the scale of the measurement is with respect to whatever the current volume of the bladder (more or less).
     
    #1 pasadena_commut, Sep 9, 2022
  2. JC91006

    JC91006 Senior Member

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    Yes I also noticed my Gen2 car being able to take in more gas at the pump. I can comfortably drive 450 miles before I fill up now, I was never able to do that comfortably (sweating bullets at the point). The heat must expand the tank bladder, can hold more than usual amount
     
    #2 JC91006, Sep 9, 2022
  3. wjtracy

    wjtracy Senior Member

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    Thank your lucky stars, we were down to 6 gal fill-up in the winter and it would not come back to normal in summer. Now we got RAVHV
     
    #3 wjtracy, Sep 9, 2022
  4. fuzzy1

    fuzzy1 Senior Member

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    In addition to softening the bladder, could high temperatures have increased the internal air / vapor pressure enough to 'inflate' the bladder and push out some wrinkles?
     
    #4 fuzzy1, Sep 10, 2022
  5. mr_guy_mann

    mr_guy_mann Senior Member

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    The bladder connects to a small reservoir that has the pump and level sensor. So the gauge shows the level of fuel in the bladder and reservoir. Since the bladder expands and contracts unevenly, the level doesn't really match the volume available. (aka, the guess gauge)

    My 2006 has "fairly" linear gauge to distance traveled in winter with its 6.5 gallon refill from flashing 1 bar.

    In summer I get 8 to 8.5 gallons, but it "holds" at 2 bars for around 90 miles, then goes past 1 bar to flashing in 30 miles.

    Posted via the PriusChat mobile app.
     
    #5 mr_guy_mann, Sep 10, 2022
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