Fuel bladder getting less flexible with age

Discussion in 'Gen 2 Prius Main Forum' started by srellim234, May 17, 2022.

  1. srellim234

    srellim234 Senior Member

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    With gas prices being what they are, my wife has finally started driving the Prius instead of the AWD SUV. Last night she asked me to fill up the car in the morning because the gas gauge has been on one bar for a while. Yikes! I've stressed over and over that we fill it up at two bars. On my 6.6 mile jaunt down the hill to Sam's Club this morning the car beeps and the one pip starts blinking. Fortunately I made it but that was a pretty good indicator the tank was rather empty.

    To the title of the thread: No 11 gallon capacity any more. The car only took 9.928 gallons at the pump's slowest fill setting. I know cold weather isn't an issue since we've been over 100*F out here for the last 4 days; in the 90s before that. Like my body, it looks like the fuel bladder is just getting less flexible with age.
     
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  2. bisco

    bisco cookie crumbler

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    that wouldn't surprise me at all, but the nature of the bladder and the emissions recovery system makes it very difficult to determine the actual problem.

    you can't even trust the gas gauge in some instances
     
  3. ChapmanF

    ChapmanF Senior Member

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    Even the beep-and-blink is designed to happen comfortably before you are really running on fumes. That you were able to put 10 gallons in, six or seven miles later, makes me think the bladder is still rather perky.
     
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  4. Tombukt2

    Tombukt2 Senior Member

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    I drive my gen too until the flashing light comes on then go 45 more miles . Fill up and have easily put 11 gallons on no issues Yet! We drive hale out of this 09 43 to 46 ripping it as it can be..
     
  5. lexidium

    lexidium Member

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    I thought it said 'full bladder less flexible with age'
    I was going to say you need to see your urologist immediately. :LOL::LOL::LOL:
     
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  6. mr_guy_mann

    mr_guy_mann Senior Member

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    Since you likely had an additional 40-50 miles in the tank, 10 gallons for a refill is just fine. My 06 gets 7 to 7-1/2 gallons after going 20-40 miles on a flashing fuel gauge. It's about a gallon less than that in winter. Since the gauge works (well enough), as does the fuel pump and it has no EVAP problems, I'm not going to replace the tank assembly just to gain a few gallons of useable capacity.

    Posted via the PriusChat mobile app.
     
  7. fuzzy1

    fuzzy1 Senior Member

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    Problem? What problem? I don't see any problem here.

    Even a Gen3 with a fixed 11.9 gallon tank, just at the point of the low fuel beep and bottom pip starting to blink, doesn't usually take quite 9.9 gallons without overfilling beyond the normal pump automatic cutoff point. In the Gen3, typically the last couple gallons is really there, but as safety margin, and some drivers often burn well down into that margin. The bottom of the gauge is not at the real bottom of the tank. See: [WARNING] Running out of gas (Gen III) | PriusChat

    Because of the fuel bladder, you probably cannot rely on your Gen2 having the same amount of reserve safety margin as a non-bladdered Gen3. But since you are getting just as much (even slightly more) refill into your tank as a Gen3 at the low fuel warning beep, I think your fuel bladder is working just fine.
     
  8. srellim234

    srellim234 Senior Member

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    Not a problem. Just an observation.

    I've put in over 10 gallons before, including the only other time it's been run down to the blinking stage. That time it took 10.9 gallons. The other 10 gallon fillups came at one solid pip or two pips just ready to switch to one. Things just get less flexible over time. As long as we continue my long-standing practice of filling up when convenient at two pips it doesn't worry me at all.
     
  9. bisco

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    again, probably a bladder issue. you never know how they will act on a certain day at a certain pump.

    the o/m tells you the tank capacity, and the 'reserve' when the light blinks, but it's not always accurate, and probably less so as the bladder ages.

    i have the same problem :oops:
     
  10. Tideland Prius

    Tideland Prius Moderator of the North
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    That’s not bad. Our Gen 2’s bladder shrunk a long time ago.
     
  11. Moving Right Along

    Moving Right Along Senior Member

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    Somebody on another forum thought I was lying when I said my car can take between 6-9 gallons of fuel, depending on weather. 10 gallons or more for a full tank would be amazing for me. But my car has been like that since I first got it over 5 years ago and it’s not really causing problems.

    So even if your fuel bladder is as constricted as mine, it probably isn’t a big deal.
     
  12. nemebean

    nemebean Junior Member

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    I would kill (well, maybe not kill, exactly) to get 10 gallons in my tank. The most I've been able to put in on a single fill is around 8, and in the winter that dropped to more like 6. Since I didn't buy the car until last fall I'm curious to see how it behaves in the middle of summer, but reduced tank capacity is one of the few big flaws with my car. 250 miles per tank in the winter means a lot of gas stops. :eek:
     
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  13. Another

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    Now you know how a Tesla owner feels and at least you don’t have to spend hours waiting to refuel.
     
  14. benjdm

    benjdm Junior Member

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    9.9 gallons? Wow. I've never been able to put more than 8 gallons in and 6 gallons is more typical.
     
  15. Wrecit

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    I read somewhere a while back that Toyota set up the Prius so that the gas gage would go to one flashing bar with several gallons still in the tank to try to encourage us dumb drivers not to run the tank dry. It had something to do with potentially hurting the battery if you run out of gas for the ICE then try to limp to the gas station and completely drain the battery before you get to sunoco. If this is the case your suspicions may be at least partially for nothing.
     
  16. Classic Car Guy

    Classic Car Guy Active Member

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    So how do you fix this random bladder phenomena?
     
  17. fuzzy1

    fuzzy1 Senior Member

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    All my traditional ICE cars over the past 40 years have given their low fuel warnings with a roughly similar remaining fuel distance, even though none of them have this hybrid battery issue.

    This isn't just for dumb Prius drivers. It is for dumb or inattentive or clueless drivers of very many vehicles, especially in areas where the next fuel station might be 50-100-ish miles ahead.

    The battery run-down issue was fixed in Gen3, but the low fuel warning still comes on at about the same fuel level.
     
  18. Another

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    In every other car I’ve owned, the dashboard was easy to read and up in your face. The fuel gage was right up there and prominent.

    The itty bitty Prius combination meter is another one of those crappy ideas that Toyota Prius engineers came up with like the bladder tank.

    Apart from being tiny, dim, and prone to needing a repair because of a cheap capacitor failure, it’s so far away from the driver that it becomes virtually inconspicuous. Maybe that’s why they give you an added margin of safety.
     
  19. nemebean

    nemebean Junior Member

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    Yes and no. The Tesla owner can plug in every night so they're always starting with 250 miles. That would drastically cut down on my refueling stops, although it wouldn't completely eliminate them.

    I've heard some people say they can go 80 miles after it starts flashing and I've heard other people run out after about 5. I haven't had the guts to really test it yet, although someday I'll throw a gas can in and give it a shot. :)
     
  20. fuzzy1

    fuzzy1 Senior Member

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    Except that my Prius doesn't have added safety margin over most of my non-hybrids. Before Prius, when their gauge needles were on 'E', they had 100+ miles of safety margin (excepting my very first, which ran out with its needle still above E). My current non-hybrid is an exception with only ~75 miles of margin, but makes up for that with more warning stages and contrasting warning light colors, which I do agree are better than the Prius dashboard design.
    On my non-bladdered Gen3, I've gone a bit over 80 miles from the point that Bob Wilson reported 122 and 132 miles to fuel starvation. But various Gen2 drivers here have reported a very wide range of results, from numerous successes at similar distances, to numerous failures less than 10 miles after the last bar starting blinking, to some failures with one or even two non-blinking bar(s). That bladder causes considerable variation.
    I've intentionally done that on two of my non-hybrids, with good results. Bob's tests were 'good enough' for me, so I didn't/haven't done it on my Prii.
     
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