Bought a new 2008 Prius in December. Noticed that the fuel tank was only holding about 6 gallons or so.

I would let the fuel gauge get down to 2 bars remaining, and it would only take 4.5 to 5 gallon on fill up.

Went back to dealer a couple times, they told me everything was fine.

Submitted a complaint to Toyota National Customer Service.

They phoned me back and said that it is "normal" for the Prius fuel tank (flexable rubber bladder) to only hold 6 gallons or so in the winter. And that the tank would not hold "rated" capacity of 11.9
gallons until after temperatures are above 70 degrees.

Just curious, how much fuel is your 2008 Prius holding, and what is the temp in your area?