2003 SUBARU IMPREZA octane

Starting and operating
7-2
Fuel
CAUTION
Use of a fuel which is low in quality or use of an inappropriate fuel additive may cause en- gine damage.
Fuel requirements
2.5 Liter models
The 2.5 Liter engine is designed to operate using
unleaded gasoline with an octane rating of 87 AKI or
higher.
2.0 Liter (turbo) models
The 2.0 Liter turbo engine is designed to operate
using premium unleaded gasoline with an octane
rating of 91 AKI or higher. If premium unleaded gas-
oline is not available, regular unleaded gasoline with an octane rating of 87 AKI or higher may be tempo-
rarily used. For optimum engine performance and
driveability, it is recommended that you use pre-
mium grade unleaded gasoline.
Fuel octane rating
This octane rating is the average of the ResearchOctane and Motor Octane numbers and is com-
monly referred to as the Anti Knock Index (AKI).Using a gasoline with a lower octane rating cancause 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 thespecified octane rating and your vehicle knocks
heavily or persistently.
Unleaded gasoline
The neck of the fuel filler pipe is designed to acceptonly an unleaded gasoline filler nozzle. Under no
circumstances should leaded gasoline be used be-
cause it will damage the emission control system
and may impair driveability and fuel economy.
Gasoline for California-certified LEV
Your vehicle was certified to California ’s low emis-
sion vehicle (LEV) standards as indicated on the
underhood tune-up label. It is designed to optimize
engine and emission performance with gasoline that
meets the clean burning low-sulfur California gaso-
line specifications. If you live in any other state than
California, your vehicle will operate on gasoline

Starting and operating
7-3
– CONTINUED –
meeting Federal specifications. Gasoline sold out-
side California is permitted to have higher sulfur lev-
els, which may affect the performance of your ve-
hicle’s catalytic converter and may produce a sulfur
exhaust odor or smell. SUBARU recommends that
you try a different brand of unleaded gasoline hav-
ing lower sulfur to determine if the problem is fuel
related before returning your vehicle to an autho-rized dealer for service.
Gasoline for cleaner air
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, youshould 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 pro-
ducing 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 detergents and oxygenates and if they have
been reformulated to reduce vehicle emissions.
As additional guidance, only use fuels suited for
your vehicle as explained below.
Fuel should be unleaded and have an octane rat-
ing no lower than that specified in this manual. Methanol (methyl or wood alcohol) is sometimes
mixed with unleaded gasoline. Methanol can beused in your vehicle ONLY if it does not exceed 5%
of the fuel mixture AND if it is accompanied by suffi-
cient quantities of the proper cosolvents and corro-
sion inhibitors required to prevent damage to the
fuel system. Do not use fuel containing methanolEXCEPT under these conditions.
If undesirable driveability problems are experi-
enced and you suspect they may be fuel related, try
a different brand of gasoline before seeking service
at your SUBARU dealer. Fuel system damage or driveability problems
which result from the use of improper fuel are not

GAS STATION REFERENCE
Fuel: 2.5 Liter models: Use only unleaded gasoline with an octane
rating of 87 AKI or higher.
2.0 Liter (Turbo) models:
Use premium unleaded gasoline with an oc-
tane rating of 91 AKI or higher. If premium un-
leaded gasoline is not available, regular un-
leaded gasoline with octane rating of 87 AKI
or higher may be temporarily used. For opti-
mum engine performance and driveability, it
is recommended that you use premium grade
unleaded gasoline. Fuel octane rating: This octane rating is the average of the Re-
search Octane and Motor Octane numbers
and is commonly referred to as the AntiKnock Index (AKI). Refer to “Fuel” section in
this manual. Fuel capacity:
15.9 US gal (60 liters, 13.2 Imp gal)
Engine oil: Use only API classification SL or SJ with the
words
“ENERGY CONSERVING ”
or the New API certification mark (starburst
mark) displayed on the container.
Engine oil capacity: Non turbo models: 4.2 US qt (4.0 liters, 3.5 Imp qt)
Turbo models: 4.8 US qt (4.5 liters, 4.0 Imp qt)
Cold tire pressure:See the label located under the driver ’s door
latch.