Chevrolet 2011 HHR Owner's Manual page 296

Many service stations will not have an 85% ethanol
fuel (E85) pump available. The U.S. Department
of Energy has an alternative fuels website
(www.afdc.energy.gov/afdc/locator/stations/) that
can help you find E85 fuel. Those stations that do
have E85 should have a label indicating ethanol
content. Do not use the fuel if the ethanol content is
greater than 85%.
At a minimum, E85 should meet ASTM Specification
D 5798. By definition, this means that fuel labeled E85
will have an ethanol content between 70% and 85%.
Filling the fuel tank with fuel mixtures that do not meet
ASTM specifications can affect driveability and could
cause the malfunction indicator lamp to come on.
To ensure quick starts in the wintertime, the E85 fuel
must be formulated properly for your climate according
to ASTM specification D 5798. If you have trouble
starting on E85, it could be because the E85 fuel is not
properly formulated for your climate. If this happens,
switching to gasoline or adding gasoline to the fuel
tank can improve starting. For good starting and heater
efficiency below 0°C (32°F), the fuel mix in the fuel tank
should contain no more than 70% ethanol. It is best
not to alternate repeatedly between gasoline and E85.
6-8
If you do switch fuels, it is recommended that you add
as much fuel as possible
(3 gal) when refueling. You should drive the vehicle
immediately after refueling for at least 11 km (7 mi) to
allow the vehicle to adapt to the change in ethanol
concentration.
E85 has less energy per liter (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 6 9.
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.
I n f o r ma t i o n P r o v i d e d b y :
do not add less than 11 L