Pumped in 10.5 Gallons

The "guess gauge" is not the most accurate thing in the world... there are plenty of posts on this . That being said, i would strongly caution everyone against topping off like the OP did here.

why, you might ask.

Well, the Prius uses a bladder system in the fuel tank to reduce emissions, and that is one of the reasons it has such a great emissions rating. Lower emissions is good for everyone, helps with global warming, etc. However, the bladder does pose a few problems. first, it makes it difficult to tell how much gas is in the tank at any given point, or even what the actual capacity of the bladder is. As the temperatures decrease here this winter, the bladder will shrink slightly. I know, it sucks.

However, when you top off like the OP, one of two things will happen. either the pump shut off early, as seemed to be the case here, and there won't be any problem for a little extra fuel. More likely, however, is that you'll be stretching the bladder more than it wants to stretch. After stretching it out (think of blowing up a balloon here), when you remove the nozzle the bladder will shrink back to it's preferred size. Like a balloon being allowed to shrink, this will cause gas to come regurgitating out of the tank and all over the side of the car, the ground, and your shoes.

While this is a waste of money and you're shoes will smell, spilling gas in this manor does one more thing: it releases emissions. In fact, a little bit of spilled gas like this will release more emissions than the Prius will on that full tank of gas.

As others have posted here numerous times, the guess gauge can't be trusted, and the bladder will regurgitate if you insist on topping off. So rather than trying to be "smarter" than the car, fill up when the gauge says its low (your choice as to when that is, blinking, one, two pips etc), and never top off - think of the environment.

 

<div class='quotetop'>QUOTE(pricoaster @ Oct 28 2006, 01:13 PM) [snapback]340054[/snapback]</div>

You have to be careful when making universal recommendations like this! What might work where you live or with your car may not work for everyone. For instance; I have never been able to get more than 9 gallons of gas in my Prius. It certainly will not work in colder climates.

This site is littered with posts about people running out of gas because of their own calculations rather than believing the blinking fuel gauge. It may be a “Guess Gauge†but you can’t go wrong filling up on 1 or 2 pips, regardless of how much it takes to fill it up.