One problem related to tank mounting has been reported for the 2008 Toyota Sienna. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2008 Toyota Sienna based on all problems reported for the 2008 Sienna.
To change a tire the floor jack was placed in front of the left rear tire a little too far toward the center (from left to right) of the vehicle. The placement appeared to be against steel but in reality the material was black plastic. When the vehicle was lifted the plastic gave way and damaged the filler pipe to the fuel tank causing fuel to be dumped to the station drive during the refueling process. It would appear that the plastic is there to protect the fuel filler pipe. This would occur each time refueling takes place. The consequences could be grave! a considerable amount of fuel was spilled because the slope of the drive was away from the operators view. Replacement of parts will correct the problem. I have requested the old parts be returned to me.