Fuel tank size

[F8L]

Originally Posted by fgoodyear

The size of the tank is 11.9 gal. I have put in as much as 11.3 when the last pip had been blinking for about 15 miles. Consider each pip as apx. 1.2 gallons.

Unfortunately it doesn't really work that way. The bladder will not always hold the exact same amount of fuel every time. I've been down to the flashing pip and I've never got more than 9.8ga or so in it. For the U.S. models anyway.

[David Beale]

Note that the OP -doesn't have a bladder fuel tank!- Overfilling it would probably not cause any problems. His tank probably holds more due to the extra space left after removing the bladder and the space in the filler pipe.

My car, with a bladder, can hold quite a bit more if filled all the way. I calculate it can hold up to 6 litres extra. Filling it -full- (fuel is seen at the top of the filler tube) WILL NOT damage the system, UNLESS you allow it to pressurize when the fuel expands. If you accidentally overfill so you see fuel sitting at the top of the filler tube, leave the cap on loosely for a few miles. If the fuel tries to expand and pressurize the tank it will just flow out and not damage the tank. This is not a good way to operate, of course, but we are talking about an accidental overfill here, something that should only happen once a year, on average.

[2009Prius]

Originally Posted by Jim Porta

I put the most gas ever (10.16 gal) in my tank last week. It wasn't on purpose. The gas pump never shut off. I had to stop it when gas overflowed over the side of my car. I've driven 197 miles so far and the fuel gage still has all it's pips. Should I be worried?

I think if the check engine light does not come on then the car should be fine. Good luck!

[Shawn Clark]

The pip increment is nowhere near 1.2 gal/pip on the average U.S. model (with bladder). The first pip can be well over 2 gallons because either the gauge or the display are unable to show above a certain level. Other pips on mine run well less than 1 gal on average. The blinking pip is only a partial pip and leaves approximately 1/8th of the volume in the tank when triggered.

It doesn't help that the U.S. model's vent system appear undersized for the job. Those fill problems we experience stem from both the complexity and undersizing of the vent lines. When you try to seal a system thoroughly (and you add an extra annulus with a large volume of air that must be displaced separately) you need considerably larger line sizes to handle it than you would on a normal tank. It's pretty easy to end up in choke flow when trying to disengage two phases moving countercurrently through a tube--particularly when the liquid entering might be flashing.

It is important to keep the discussion of the bladder and bladderless types separate as you can't necessarily apply one to the other. If Toyota uses the same shell volume for the non-bladder models then one would expect them to have a larger actual volume. I don't know if they did that or not. Their claimed volume for the non-bladder models would indicate they did not. Considering Toyota's history with oil fill volumes I wouldn't bet on it...

Even if the bladder volume and the non-bladder tank volume were identical the regular tank should have a wider working range than the notorious bladder. Loss of some working range is one of the handicaps that comes with the bladder.