GMC 2009 Savana - Manual (Page 251)

If you do switch fuels, it is recommended that you
add as much fuel as possible — do not add less
than three gallons (11 L) when refueling. You should
drive the vehicle immediately after refueling for at least
seven miles (11 km) to allow the vehicle to adapt to the
change in ethanol concentration.
E85 has less energy per gallon than gasoline, so you
will need to refill the fuel tank more often when using E85
than when you are using gasoline. See Filling the Tank
on page 5-10.
Notice: Some additives are not compatible with
E85 fuel and can harm the vehicle’s fuel system.
Do not add anything to E85. Damage caused
by additives would not be covered by the vehicle
warranty.
Notice: This vehicle was not designed for fuel
that contains methanol. Do not use fuel containing
methanol. It can corrode metal parts in the fuel
system and also damage plastic and rubber parts.
That damage would not be covered under the
vehicle warranty.
Fuels in Foreign Countries
If you plan on driving in another country outside the
United States or Canada, the proper fuel might be hard
to find. Never use leaded gasoline or any other fuel
not recommended in the previous text on fuel. Costly
repairs caused by use of improper fuel would not
be covered by the vehicle warranty.
To check the fuel availability, ask an auto club, or
contact a major oil company that does business in the
country where you will be driving.
5-9