Toyota Sienna 2010 Owner's Manual page 107

1-5. Refueling
Closing the fuel tank cap
Fuel type
■
Unleaded gasoline (Octane rating 87 [Research Octane Number 91] or
higher)
Fuel tank capacity (reference)
■
20.9 gal. (79 L, 17.5 Imp. gal.)
108
When replacing the fuel tank
cap, turn it until a clicking sound
is heard.
After releasing your hand, the cap
will turn slightly to the opposite
direction.