engine SUBARU IMPREZA 2007 3.G Repair Manual

exhaust fumes are entering the
vehicle, have the problem
checked and corrected as soon
as possible. If you must drive
under these conditions, drive
only with all windows fully open.
. Keep the trunk lid (Sedan) or rear
gate (Wagon) closed while driv-
ing to prevent exhaust gas from
entering the vehicle.
NOTE
Due to the expansion and contraction
of the metals used in the manufacture
of the exhaust system, you may hear a
crackling sound coming from the ex-
haust system for a short time after the
engine has been shut off. This sound isnormal. Catalytic converter
Turbo models
Non-turbo models
The catalytic converter is installed in the
exhaust system. It serves as catalyst to reduce HC, CO and NOx in exhaust
gases, thus providing cleaner exhaust.
To avoid damage to the catalytic conver- ter: .
Use only unleaded fuel. Even a small
amount of leaded fuel will damage the
catalytic converter. . Never start the engine by pushing or
pulling the vehicle.. Avoid racing the engine.
. Never turn off the ignition switch while
the vehicle is moving.. Keep your engine tuned-up. If you feel
the engine running rough (misfiring, back-
firing or incomplete combustion), have
your vehicle checked and repaired by an
authorized SUBARU dealer. . Do not apply undercoating or rust
prevention treatment to the heat shield of
catalytic converter and the exhaust sys-tem.
WARNING
. Avoid fire hazards. Do not drive
or park the vehicle anywhere
near flammable materials (e.g.
grass, paper, rags or leaves),
because the catalytic converter
operates at very high tempera-tures. Driving tips
8-3
– CONTINUED –

8-4Driving tips
.Keep everyone and flammable
materials away from the exhaust
pipe while the engine is running.
The exhaust gas is very hot. Periodic inspections
To keep your vehicle in the best condition
at all times, always have the recom-
mended maintenance services listed in
the maintenance schedule in the
“War-
ranty and Maintenance Booklet ”per-
formed at the specified time or mileageintervals. Driving in foreign countries
When planning to use your vehicle in
another country: .
Confirm the availability of the correct
fuel. (Refer to the “Fuel requirements ”
section in chapter 7.). Comply with all regulations and re-
quirements of each country.

Driving tips for AWD vehicles
All-Wheel Drive distributes the engine
power to all four wheels. AWD vehicles
provide better traction when driving on
slippery, wet or snow-covered roads and
when moving out of mud, dirt and sand.
By shifting power between the front and
rear wheels, SUBARU AWD can also
provide added traction during acceleration
and added engine braking force duringdeceleration.
Therefore, your SUBARU AWD vehicle
may handle differently than an ordinary
two wheel drive vehicle and it contains
some features unique to AWD. For safety
purposes as well as to avoid damaging
the AWD system, you should keep the
following tips in mind:.
An AWD vehicle is better able to climb
steeper roads under snowy or slippery
conditions than a two wheel drive vehicle.
There is little difference in handling,
however, during extremely sharp turns or
sudden braking. Therefore, when driving
down a slope or turning corners, be sure
to reduce your speed and maintain an
ample distance from other vehicles. . When replacing a tire, make sure you
use only the same size, construction,
brand, and load range as the original tires
listed on the tire placard. Using other
sizes, circumference or construction may
result in severe mechanical damage to the
drive train of your vehicle and may affect
ride, handling, braking, speedometer/od-
ometer calibration, and clearance be-
tween the body and tires. It also may be
dangerous and lead to loss of vehiclecontrol. . If you use a temporary spare tire to
replace a flat tire, be sure to use the
original temporary spare tire stored in the
vehicle. Using other sizes may result in
severe mechanical damage to the drive
train of your vehicle. . Always check the cold tire pressure
before starting to drive. The recom-
mended tire pressure is provided on the
tire placard, which is located under the
door latch on the driver ’s side. .
Tire chains should always be placed on
the front wheels only. . There are some precautions that you
must observe when towing your vehicle.
For detail information, see the “Towing ”
section in chapter 9.
WARNING
. Always maintain a safe driving
speed according to the road and
weather conditions in order to
avoid having an accident on a
sharp turn, during sudden brak-
ing or under other similar condi-tions.
. Always use the utmost care in
driving –overconfidence be-
cause you are driving an All-
Wheel Drive vehicle could easily
lead to a serious accident. Driving tips
8-5

8-6Driving tips
Off road driving
WARNING
. Always maintain a safe driving
speed according to the road and
weather conditions in order to
avoid having an accident on a
sharp turn, during sudden brak-
ing or under other similar condi-tions.
. Always use the utmost care in
driving –overconfidence be-
cause you are driving an All-
Wheel Drive vehicle could easily
lead to a serious accident.
CAUTION
Do not drive on rough roads or over
curbs in a vehicle that has 17-inch
or other ultra-low-profile tires. The
wheels and tires could be damaged
by shock forces, leading to abnor-
mal vibration or poor straight-line
tracking. Driving would then be
more difficult. &
All AWD models except
OUTBACK SPORT
Your AWD vehicle is neither a conven-
tional off-road vehicle nor an all terrain
vehicle. It is a passenger vehicle designed
primarily for on-road use. The AWD
feature gives it some limited off-road
capabilities in situations in which driving
surfaces are relatively level, obstruction-
free and otherwise similar to on-road
driving conditions. Operating it under other
than those conditions could subject the
vehicle to excessive stress which might
result in damage not eligible for repair
under warranty. If you do take your
SUBARU off-road, you should review the
common sense precautions in the next
section (applicable to the OUTBACK
SPORT) for general guidance. But please
keep in mind that your vehicle ’s off-road
capabilities are more limited than those of
the OUTBACK SPORT.
Never attempt to drive through pools and
puddles, or roads flooded with water.
Water entering the engine air intake or
the exhaust pipe or water splashing onto
electrical parts may damage your vehicle
and may cause it to stall. & OUTBACK SPORT
Your Subaru can be driven on ordinary roads or off-road. But please keep in mind
that an AWD SUBARU is a passenger
vehicle and is neither a conventional off-
road vehicle nor an all-terrain vehicle. If
you do take your SUBARU off-road,
certain common sense precautions such
as the following should be taken: .
Make certain that you and all of your
passengers are wearing seatbelts.. Carry some emergency equipment,
such as a towing rope or chain, a shovel,
wheel blocks, first aid kit and cell phone or
citizens band radio. . Drive carefully. Do not take unneces-
sary risks by driving in dangerous areas or
over rough terrain. . Slow down and employ extra caution at
all times. When driving off-road, you will
not have the benefit of marked traffic
lanes, banked curves, traffic signs and
the like. . Do not drive across steep slopes.
Instead, drive either straight up or straight
down the slopes. A vehicle can much
more easily tip over sideways than it can
end over end. Avoid driving straight up or
down slopes that are too steep. . Avoid sharp turning maneuvers, espe-
cially at higher speeds.. Do not grip the inside or spokes of the
steering wheel. A bad bump could jerk the
wheel and injure your hands. Instead drive

with your fingers and thumbs on the
outside of the rim. .If driving through water, such as when
crossing shallow streams, first check the
depth of the water and the bottom of the
stream bed for firmness and ensure that
the bed of the stream is flat. Drive slowly
and completely through the stream. The
water should be shallow enough that it
does not reach the vehicle ’s undercar-
riage. Water entering the engine air intake
or the exhaust pipe or water splashing
onto electrical parts may damage your
vehicle and may cause it to stall. Never
attempt to drive through rushing water;
regardless of its depth, it can wash away
the ground from under your tires, resulting
in possible loss of traction and even
vehicle rollover. . Always check your brakes for effec-
tiveness immediately after driving in sand,
mud or water. Do this by driving slowly
and stepping on the brake pedal. Repeat
that process several times to dry out the
brake discs and brake pads. . Do not drive or park over or near
flammable materials such as dry grass or
fallen leaves, as they may burn easily. The
exhaust system is very hot while the
engine is running and right after the
engine stops. This could create a firehazard. .
After driving through tall grass, mud,
rocks, sand, rivers, etc., check that there
is no grass, bush, paper, rags, stones,
sand, etc. adhering to or trapped on the
underbody. Clear off any such matter from
the underbody. If the vehicle is used with
these materials trapped or adhering to the
underbody, a mechanical breakdown or
fire could occur. . Secure all cargo carried inside the
vehicle and make certain that it is not
piled higher than the seatbacks. During
sudden stops or jolts, unsecured cargo
could be thrown around in the vehicle and
cause injury. Do not pile heavy loads on
the roof. Those loads raise the vehicle ’s
center of gravity and make it more prone
to tip over. . If you must rock the vehicle to free it
from sand or mud, depress the accelerator
pedal slightly and move the selector lever
back and forth between “D ” and “R ”
repeatedly. Do not race the engine. For
the best possible traction, avoid spinning
the wheels when trying to free the vehicle.
When the road surface is extremely
slippery, you can obtain better traction by
starting the vehicle with the transmission
in 2nd than 1st (both for MT and AT). . Never equip your vehicle with tires
larger than those specified in this manual.. Frequent driving of an AWD vehicle under hard-driving conditions such as
rough roads or off roads will necessitate
more frequent replacement of engine oil,
brake fluid and transmission oil than that
specified in the maintenance schedule
described in the
“Warranty and Mainte-
nance Booklet ”.
Remember that damage done to your
Subaru while operating it off-road and
not using common sense precautions
such as those listed above is not eligible
for warranty coverage. . Wash the vehicle ’s underbody after off-
road driving. Suspension components are
particularly prone to dirt buildup, so they
need to be washed thoroughly. Driving tips
8-7

8-8Driving tips
Winter driving
&Operation during cold weather
Carry some emergency equipment, such
as tire chains, a window scraper, a bag of
sand, flares, a small shovel, and jumpercables.
Check the battery and cables. Cold
temperatures reduce battery capacity.
The battery must be in good condition to
provide enough power for cold winterstarts.
Use an engine oil of proper grade and
viscosity for cold weather. Heavy summer
oil will cause harder starting.
Keep the door locks from freezing by squirting them with deicer or glycerin.
Forcing a frozen door open may damage
or separate the rubber weather strips
around the door. If the door is frozen,
use hot water to melt the ice, and after-
wards thoroughly wipe the water away.
Use a windshield washer fluid that con-
tains an antifreeze solution. Do not use
engine antifreeze or other substitutes
because they may damage the paint of
the vehicle.
SUBARU Windshield Washer Fluid con-
tains 58.5% methyl alcohol and 41.5%
surfactant, by volume. Its freezing tem-
perature varies according to how much it
is diluted, as indicated in the followingtable.
Washer Fluid Con- centration Freezing Temperature
30% 10.4 8F( 12 8C)
50% 48F( 20 8C)
100%
49 8F( 45 8C)
In order to prevent freezing of washer
fluid, check the freezing temperatures in
the table above when adjusting the fluid
concentration to the outside temperature.
If you fill the reservoir tank with a fluid with
a different concentration from the one used previously, purge the old fluid from
the piping between the reservoir tank and
washer nozzles by operating the washer
for a certain period of time. Otherwise, if
the concentration of the fluid remaining in
the piping is too low for the outside
temperature, it may freeze and block thenozzles.
CAUTION
Adjust the washer fluid concentra-
tion appropriately for the outside
temperature. If the concentration is
inappropriate, sprayed washer fluid
may freeze on the windshield and
obstruct your view, and the fluid
may freeze in the reservoir tank.
! Before driving your vehicle
Before entering the vehicle, remove any
snow or ice from your shoes because that
could make the pedals slippery anddangerous.
While warming up the vehicle before
driving, check that the accelerator pedal,
brake pedal, and all other controls operate
smoothly.
Clear away ice and snow that has
accumulated under the fenders to avoid
making steering difficult. During severe

winter driving, stop when and where it is
safe to do so and check under the fenders
periodically. !Parking in cold weather
Do not use the parking brake when
parking for long periods in cold weather
since it could freeze in that position.
Instead, observe the following.
1. Place the shift lever in “1 ” or “R ” for
manual transmission vehicles, and in “P ”
for automatic transmission vehicles.
2. Use tire stops under the tires to
prevent the vehicle from moving.
When the vehicle is parked in snow or
when it snows, raise the wiper blades off
the glass to prevent damage to them.
When the vehicle has been left parked
after use on roads heavily covered with
snow, or has been left parked during a
snowstorm, icing may develop on the
brake system, which could cause poor
braking action. Check for snow or ice
buildup on the suspension, disc brakes
and brake hoses underneath the vehicle.
If there is caked snow or ice, remove it,
being careful not to damage the disc
brakes and brake hoses and ABS har-ness.WARNING
Snow can trap dangerous exhaust
gases under your vehicle. Keep
snow clear of the exhaust pipe and
from around your vehicle if you park
the vehicle in snow with the enginerunning.
! Refueling in cold weather
To help prevent moisture from forming in
the fuel system and the risk of its freezing,
use of an antifreeze additive in the fuel
tank is recommended during cold weather.
Use only additives that are specifically
designed for this purpose. When an
antifreeze additive is used, its effect lasts
longer if the tank is refilled whenever the
fuel level reaches half empty.
If your SUBARU is not going to be used
for an extended period, it is best to have
the fuel tank filled to capacity. & Driving on snowy and icy roads
To prevent skidding and slipping, avoid
sudden braking, abrupt acceleration, high-
speed driving, and sharp turning when
driving on snowy or icy roads.
Always maintain ample distance between
your vehicle and the vehicle ahead of you to avoid the need for sudden braking.
To supplement the foot brake, use the
engine brake effectively to control the
vehicle speed. (Shift into a lower gear
when necessary.)
Avoid shifting down abruptly. Such beha-
vior can cause the wheels to lock, possibly
leading to loss of vehicle control.
An anti-lock brake system (ABS) en-
hances your vehicle
’s braking perfor-
mance on snowy and icy roads. Refer tothe “ABS (Anti-lock Brake System) ”sec-
tion in chapter 7 for information on braking
on slippery surfaces.
NOTE
The following tires are summer tires.
Compared with winter and all-season
tires, summer tires give significantly
less grip on snowy and icy road
surfaces. Avoid driving on snowy and
icy road surface with summer tires. . 225/45R17 tires for WRX-STI
WARNING
Do not use the cruise control on
slippery roads such as snowy or icy
roads. This may cause loss of
vehicle control. Driving tips
8-9
– CONTINUED –

8-10Driving tips
CAUTION
Avoid prolonged continuous driving
in snowstorms. Snow will enter the
engine ’s intake system and may
hinder the air flow, which could
result in engine shutdown or evenbreakdown.
! Wiper operation when snowing
Before driving in cold weather, make sure
the wiper blades are not frozen to the
windshield or rear window. If the wiper
blades are frozen to the windshield or rear
window, use the defroster with the airflow
control dial in the “
”position and the
temperature control dial set for maximum
warmth until the wiper blades are com-
pletely thawed out. If your vehicle is
equipped with a wiper deicer, it is helpful
to thaw the windshield wiper blades. To
thaw out the rear wiper blade, use the rear
window defogger.
When driving in snow, if frozen snow starts
to stick on the surface of the windshield
despite wiper operation, use the defroster
with the airflow control dial in “
”and the
temperature control dial set for maximum
warmth. After the windshield gets warmed
enough to melt the frozen snow on it,
wash it away using the windshield washer. Snow stuck on the wiper arm prevents the
wiper from working effectively. If snow is
stuck on the wiper arm, pull off the road to
a safe place, then remove it. If you stop
the vehicle at road side, use the hazard
warning flasher to alert other drivers.
We recommend use of non-freezing type
wiper blades (winter blades) during the
seasons you could have snow and sub-
zero temperatures. Blades of this type
give superior wiping performance in
snowy conditions. Be sure to use blades
that are suitable for your vehicle.
CAUTION
During high-speed driving, non-
freezing type wiper blades may not
perform as well as standard wiper
blades. If this happens, reduce the
vehicle speed.
NOTE
When the season requiring non-freez-
ing type wiper blades is over, replace
them with standard wiper blades. & Corrosion protection
Refer to the “Corrosion protection ”section
(chapter 10). &
Snow tires
! All models except WRX-STI
WARNING
. When replacing original tires with
winter (snow) tires, make sure
you use only the same size,
construction and load range as
the original tires listed on the tire
placard. Using other sizes and
construction may affect speed-
ometer/odometer calibration and
clearance between the body and
tires. It also may be dangerous
and lead to loss of vehicle con-trol.
. You must install four winter tires
that are of the same size, con-
struction, brand, and load range.
Mixing other sizes or construc-
tions may result in severe me-
chanical damage to the drive
train of your vehicle and may
affect ride, handling, braking and
speedometer/odometer calibra-
tion. It also may be dangerous
and lead to loss of vehicle con-trol.
. Do not use a combination of
radial, belted bias or bias tires

8-12Driving tips
speeds below 19 mph (30 km/h).
When a temporary spare tire is on a front
wheel, replace the temporary spare tire
with the rear tire on the same side of the
vehicle, and then fit chains on the front tires.
Always use the utmost care when driving
with tire chains —overconfidence be-
cause you are driving with tire chains
could easily lead to a serious accident.
CAUTION
Tire chains cannot be used on tires
listed in the following because of
lack of clearance between the tires
and vehicle body. . 225/45R17 tires for WRX-STI
. 215/45R17 tires for WRX
& Rocking the vehicle
If you must rock the vehicle to free it from
snow, sand, or mud, depress the accel-
erator pedal slightly and move the selector
lever back and forth between “D ”and “R ”
repeatedly. Do not race the engine. For
the best possible traction, avoid spinning
the wheels when trying to free the vehicle.
When the road surface is extremely
slippery, you can obtain better traction by starting the vehicle with the transmission
in 2nd than 1st (both for MT and AT).
Refer to the
“Automatic transmission ”
section in chapter 7 for information on
holding the transmission in 2nd position. Loading your vehicle
WARNING
. Never allow passengers to ride
on a folded rear seatback, in the
trunk or in the cargo area. Doing
so may result in serious injury.
. Never stack luggage or other
cargo higher than the top of the
seatback because it could tumble
forward and injure passengers in
the event of a sudden stop or
accident. Keep luggage or cargo
low, as close to the floor aspossible.

8-20Driving tips
Trailer towing
Your vehicle is designed and intended to
be used primarily as a passenger-carrying
vehicle. Towing a trailer puts additional
loads on your vehicle ’s engine, drivetrain,
brakes, tires and suspension and has an
adverse effect on fuel economy.
If you do decide to tow a trailer, your safety
and satisfaction depend upon proper use
of correct equipment and cautious opera-
tion of your vehicle. Seek the advice of
your SUBARU dealer to assist you in
purchasing a hitch and other necessary
towing equipment appropriate for your
vehicle. In addition, be sure to follow the
instructions on correct installation and use
provided by the trailer and other towing
equipment manufacturers.
SUBARU assumes no responsibility for
injuries or vehicle damage that result from
trailer towing equipment, or from any
errors or omissions in the instructions
accompanying such equipment or for your
failure to follow the proper instructions.
& Warranties and maintenance
SUBARU warranties do not apply to
vehicle damage or malfunction caused
by trailer towing. If you use your vehicle to
tow a trailer, more frequent maintenance
will be required due to the additional load. (Refer to
“Maintenance schedule under
severe driving conditions ”in the “Warranty
and Maintenance Booklet ”.)
Under no circumstances should a trailer
be towed with a new vehicle or a vehicle
with any new powertrain component (en-
gine, transmission, differential, wheel
bearings, etc.) for the first 1,000 miles
(1,600 km) of driving.
& Maximum load limits
WARNING
Never exceed the maximum load
limits explained in the following.
Exceeding the maximum load limits
could cause personal injury and/or
vehicle damage.
CAUTION
. Adequate size trailer brakes are
required when the trailer and its
cargo exceed 1,000 lbs (453 kg)
total weight.
. Before towing a trailer, check the
trailer total weight, GVW, GAWs
and tongue load. Make sure the
load and its distribution in your
vehicle and trailer are accepta- ble.
! Total trailer weight
Total trailer weight
The total trailer weight (trailer weight plus
its cargo load) must never exceed the
maximum weight shown in the followingtable.