Fuel Additives; E85 Or Flexfuel - GMC Sierra Instruction Manual

318 Driving and Operating
fuel not recommended. Costly
repairs caused by use of improper
fuel would not be covered by the
vehicle warranty.

Fuel Additives

To keep fuel systems clean, TOP
TIER Detergent Gasoline is
recommended. See Fuel 0 316.
If TOP TIER Detergent Gasoline is
not available, one bottle of Fuel
System Treatment PLUS added to
the fuel tank at every engine oil
change can help. Fuel System
Treatment PLUS is the only
gasoline additive recommended by
General Motors. It is available at
your dealer.
Do not use additives with E85 or
FlexFuel.

E85 or FlexFuel

Vehicles with a yellow fuel cap can
use either unleaded gasoline or fuel
containing up to 85% ethanol (E85).
All other vehicles should use only
the unleaded gasoline as described
in Fuel 0 316.
The use of E85 or FlexFuel is
encouraged when the vehicle is
designed to use it. E85 or FlexFuel
is made from renewable sources.
To help locate fuel stations that
carry E85 or FlexFuel, the U.S.
Department of Energy has an
alternative fuels website. See
www.afdc.energy.gov/afdc/locator/
stations.
E85 or FlexFuel should meet ASTM
Specification D 5798 or CAN/
CGSB 3.512 in Canada. Do not use
the fuel if the ethanol content is
greater than 85%. Fuel mixtures that
do not meet ASTM or CGSB
specifications can affect driveability
and could cause the malfunction
indicator lamp to come on.
For the 6.0L V8 engine, after
refueling, the vehicle calculates the
composition of the fuel. It is not
recommended to repeatedly switch
between fuels. If fuels are switched
frequently, add as much fuel as
possible and do not add less than
11 L (3 gal) when refueling. Drive at
least 11 km (7 mi) immediately after
I n f o r ma t i o n P r o v i d e d b y :
refueling to allow the vehicle to
adapt to the change in ethanol
concentration.
Because E85 or FlexFuel has less
energy per liter (gallon) than
gasoline, the vehicle will need to be
refilled more often. See Filling the
Tank 0 319.
Caution
Some additives are not
compatible with E85 or FlexFuel
and can harm the vehicle's fuel
system. Do not add anything to
E85 or FlexFuel. Damage caused
by additives would not be covered
by the vehicle warranty.
Caution
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.