2010 SUBARU LEGACY octane

7-2Starting and operating
Fuel
CAUTION
Use of a fuel which is low in quality
or use of an inappropriate fuel
additive may cause engine damage.
& Fuel requirements
! Non-turbo models
The non-turbo engine is designed to
operate using unleadedgasoline with an
octane rating of 87 AKI or higher .
! Turbo models
The engine is designed to operate at
maximum performance using unleaded
gasoline with an octane rating of 93 AKI
or higher . If 93 AKI fuel is not readily
available in your area, unleaded gasoline
with an octane rating of 91 AKI may be
used with no detriment to engine durability
or driveability. However, you may notice a
slight decrease in maximum engine per-
formance while using 91 AKI fuel. Use of
91 AKI fuel will not affect your warranty
coverage. If premium unleaded gasoline is
not available, regular unleaded gasoline
with an octane rating of 87 AKI or higher
may be temporarily used. For optimum engine performance and driveability, it is
required that you use premium grade
unleaded gasoline.
NOTE
Be sure to use premium unleaded
gasoline of 91 AKI or higher for a turbo
engine model. If other gasoline (lower
than 91 AKI) is used, knocking, re-
duced output and poor accelerator
response will result. ! Fuel octane rating
This octane rating is the average of the
Research Octane and Motor Octane
numbers and is commonly referred to as
the Anti Knock Index (AKI).
Using a gasoline with a lower octane
rating can cause persistent and heavy
knocking, which can damage the engine.
Do not be concerned if your vehicle
sometimes knocks lightly when you drive
up a hill or when you accelerate. See your
dealer or a qualified service technician if
you use a fuel with the specified octane
rating and your vehicle knocks heavily or
persistently. ! Unleaded gasoline
The neck of the fuel filler pipe is designed
to accept only an unleaded gasoline filler
nozzle. Under no circumstances should
leaded gasoline be used because it will damage the emission control system and
may impair driveability and fuel economy. !
California fuel
If your vehicle was certified to California
Emission Standards as indicated on the
underhood tune-up label, it is designed to
optimize engine and emission control
system performance with gasoline that
meets the clean burning low-sulfur Cali-
fornia gasoline specifications. If you live in
any other state than California, your
vehicle will operate on gasoline meeting
Federal specifications. Gasoline sold out-
side California is permitted to have higher
sulfur levels, which may affect the perfor-
mance of your vehicle ’s catalytic converter
and may produce a sulfur exhaust odor or
smell. SUBARU recommends that you try
a different brand of unleaded gasoline
having lower sulfur to determine if the
problem is fuel related before returning
your vehicle to an authorized dealer for
service. The CHECK ENGINE warning
light/malfunction indicator lamp may also
turn on. If this occurs, return to your
authorized SUBARU dealer for diagnosis.
If it is determined that the condition is
caused by the type of fuel used, repairs
may not be covered by your warranty.

!MMT
Some gasoline contains an octane-en-
hancing additive called MMT (Methylcy-
clopentadienyl Manganese Tricarbonyl). If
you use such fuels, your emission control
system performance may deteriorate and
the CHECK ENGINE warning light/mal-
function indicator lamp may turn on. If this
happens, return to your authorized
SUBARU Dealer for service. If it is
determined that the condition is caused
by the type of fuel used, repairs may not
be covered by your warranty. ! Gasoline for cleaner air
CAUTION
Do not let fuel spill on the exterior
surfaces of the vehicle. Fuels con-
taining alcohol may cause paint
damage, which is not covered under
the SUBARU Limited Warranty.
Your use of gasoline with detergent
additives will help prevent deposits from
forming in your engine and fuel system.
This helps keep your engine in tune and
your emission control system working
properly, and is a way of doing your part
for cleaner air. If you continuously use a
high quality fuel with the proper detergent
and other additives, you should never need to add any fuel system cleaning
agents to your fuel tank.
Many gasolines are now blended with
materials called oxygenates. Use of these
fuels can also help keep the air cleaner.
Oxygenated blend fuels, such as MTBE
(Methyl Tertiary Butyl ether) or ethanol
(ethyl or grain alcohol) may be used in
your vehicle, but should contain no more
than 15% MTBE or 10% ethanol for the
proper operation of your SUBARU.
In addition, some gasoline suppliers are
now producing reformulated gasolines,
which are designed to reduce vehicle
emissions. SUBARU approves the use of
reformulated gasoline.
If you are not sure what the fuel contains,
you should ask your service station
operators if their gasolines contain deter-
gents and oxygenates and if they have
been reformulated to reduce vehicle emis-sions.
As additional guidance, only use fuels
suited for your vehicle as explained in thefollowing. .
Fuel should be unleaded and have an
octane rating no lower than that specified
in this manual. . Methanol (methyl or wood alcohol) is
sometimes mixed with unleaded gasoline. Methanol can be used in your vehicle
ONLY
if it does not exceed 5% of the fuel
mixture ANDif it is accompanied by
sufficient quantities of the proper cosol-
vents and corrosion inhibitors required to
prevent damage to the fuel system. Do not
use fuel containing methanol EXCEPT
under these conditions. . If undesirable driveability problems are
experienced and you suspect they may be
fuel related, try a different brand of gaso-
line before seeking service at your
SUBARU dealer. . Fuel system damage or driveability
problems which result from the use of
improper fuel are not covered under the
SUBARU Limited Warranty.
& Fuel filler lid and cap
! Refueling
Only one person should be involved in
refueling. Do not allow others to approach
the area of the vehicle near the fuel filler
pipe while refueling is in progress.
Be sure to observe any other precautions
that are posted at the service station. Starting and operating
7-3
– CONTINUED –

GAS STATION REFERENCE
& Fuel:
! Non-turbo models
Use only unleaded gasoline with an octane rating of 87 AKI or
higher .
! Turbo models
Use premium unleaded gasoline with an octane rating of 93
AKI or higher . For temporary purposes if premium unleaded
gasoline is not available, you may use regular unleaded
gasoline with an octane rating of 87 AKI or higher. For optimum
engine performance and driveability, it is required that you use
premium grade unleaded gasoline. & Fuel octane rating
This octane rating is the average of the Research Octane and
Motor Octane numbers and is commonly referred to as the Anti
Knock Index (AKI). Refer to “Fuel ”F 7-2 section in this manual. &
Fuel capacity:
18.5 US gal (70 liters, 15.4 Imp gal) & Engine oil:
Use only API classification SM with the words “ENERGY
CONSERVING ”or ILSAC GF-4, which can be identified with
the ILSAC certification mark (Starburst mark).
For the complete viscosity requirements, refer to the following sections.. “Recommended grade and viscosity ”F 11-16
. “Recommended grade and viscosity under severe driving
conditions ”F 11-17
& Engine oil capacity:
2.5 L models: 4.2 US qt (4.0 liters, 3.5 Imp qt)
3.6 L models: 6.7 US qt (6.3 liters, 5.5 Imp qt)