Bladder Gas Tank ?

The good news is that the 2010 doesn't. It's a nuisance in freezing weather because it cuts the tank capacity by at least a gallon.

I've never seen one of the tanks cut open but my conceptualization of the tank is that there is a rubber bladder inside the plastic fuel tank and the rubber bladder 'shrivels' up as the fuel is emptied from the tank and then unshrivels when it is refilled. The idea of the collapsible rubber bladder is to eliminate the vapor space in the tank to improve fuel economy and reduce vapor air emissions. Anyway, a fine idea but I notice that the refillable volume changes with every refill because the rubber bladder does not always unshrivel completeley...or at least that's my concept of how it is working...so that the tank volume can be 1 to 2 gallons less than maximum if you stop filling at the first 'clunk' off from the fuel nozzle. I've found that you can still fill that gallon or so if you continue to squeeze the refueling nozzle trigger repeatedly to 'top off' the tank as the last few wrinkles in the rubber bladder pop open. You should never do that with any car with a conventional fuel tank and charcoal cannister but with the prius it's okay...or so it seems.

On two occasions I've witnessed what appears to be another bladder related phenomomena.

The car pukes about 1/2 pint of gas as the nozzle is removed.

Perhaps such a tight seal exists between the nozzle and port to permit stretching the bladder as gas is forced into the tank and the gas is puked-out as the bladder relaxes when the pressure is released, much like what happens when you drink a lot of beer in a very short period.

Perhaps the gas sloshes around if the bladder suddenly unfolds.

MY Prius has never puked gas. Maybe your prius was up late the night before.

Then look here:

Many thanks to BobJ for the informative reference :

Hope the folks at Toyota have reliable components in this complicated system !

Does Toyota have reliable components? Does the Pope have a Crucifix?

Davoud