2012 SUBARU IMPREZA WRX engine

Air cleaner element
WARNING
Do not operate the engine with the
air cleaner element removed. The air
cleaner element not only filters
intake air but also stops flames if
the engine backfires. If the air
cleaner element is not installed
when the engine backfires, you
could be burned.
CAUTION
When replacing the air cleaner ele-
ment, use a genuine SUBARU air
cleaner element. If it is not used,
there is the possibility of causing a
negative effect to the engine.
The air cleaner element functions as a
filter screen. When the element is perfo-
rated or removed, engine wear will be
excessive and engine life shortened.
It is not necessary to clean or wash the air
cleaner element. &
Replacing the air cleaner element
Replace the air cleaner element according
to the maintenance schedule in the“ Warranty and Maintenance Booklet ”. Un-
der extremely dusty conditions, replace it
more frequently. It is recommended that
you always use genuine SUBARU parts.
1. Use a screwdriver to undo the clips on
the air intake duct, then remove the air
intake duct.
1) Connector
2) Clip
2. Unplug the connector that is attached
to the top of the air cleaner case.
3. Unsnap the two clips holding the air
cleaner case cover.
Maintenance and service 11-13
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Drive belts
1) Power steering oil pump pulley
2) Front side belt
3) Alternator pulley
4) Air conditioner compressor pulley
5) Rear side belt
6) Crank pulley
A) 22 lbf (98 N, 10 kgf)
CAUTION
The front side belt, which runs in
conjunction with the following com-
ponents, must be used within the
specified deflection. . Power steering oil pump pulley
. Alternator pulley
. Crank pulley Check the deflection of the front
side belt and if there is any loosen-
ess, cracks, wear or unusual noise
on the front side belt, contact your
SUBARU dealer.
Continuing to use the vehicle with
the belt outside of the specification
may cause the engine to malfunc-
tion and the above components tomalfunction.
To check the deflection of the front side
belt, place a straightedge (ruler) across
two adjacent pulleys (alternator pulley and
crank pulley) and apply a force of 22 lbf
(98 N, 10 kgf) midway between the pulleys
by using a spring scale. The belt deflec-
tion should be the amount specified. If the
front side belt is loose, cracked or worn,
contact your SUBARU dealer. in (mm)
Deflection
New belt Used belt
A 0.28
–0.35
(7.0 –9.0) 0.35
–0.43
(9.0 –11.0)
The rear side belt is a stretch-type belt,
therefore the deflection does not need to
be checked. If there are cracks or wear
confirmed on the belts and a squeaking
noise is heard from them, contact your
SUBARU dealer. Manual transmission oil &
Checking the oil level
Except STI
Check the oil level monthly.
1. Park the vehicle on a level surface and
stop the engine.
2. Pull out the level gauge, wipe it clean,
and insert it again. Maintenance and service
11-15
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Power steering fluid &Checking the fluid level
The power steering fluid expands greatly
as its temperature rises; the fluid level
differs according to fluid temperature.
Therefore, the reservoir tank has two
different checking ranges for hot and cold fluids.
Check the power steering fluid level
monthly.
1. Park the vehicle on a level surface,
and stop the engine.
2. Check the fluid level of the reservoir tank.
When the fluid is hot after the vehicle has
been run: Check that the oil level isbetween “HOT MIN ”and “HOT MAX ”on
the surface of the reservoir tank.
When the fluid is cool before the vehicle is
run: Check that the oil level is between“ COLD MIN ”and “COLD MAX ”on the
surface of the reservoir tank.
3. If the fluid level is lower than the
applicable “MIN ”line, add the recom-
mended fluid as necessary to bring the
level between the “MIN ”and “MAX ”line.
If the fluid level is extremely low, it may
indicate possible leakage. Consult your
SUBARU dealer for an inspection.
WARNING
Be careful not to burn yourself
because the fluid may be hot.
CAUTION
. When power steering fluid is
being added, use only clean fluid,
and be careful not to allow any
dirt into the tank. And never use
different brands together.
. Be careful not to spill power
steering fluid when adding it. If
power steering fluid touches the
exhaust pipe, it may cause a bad
smell, smoke, and/or a fire. If
power steering fluid gets on the
exhaust pipe, be sure to wipe it off.
& Recommended fluid
Refer to “Fluids ”F 12-7.
Maintenance and service
11-17

11-20Maintenance and service
Brake booster
If the brake booster does not operate as
described in the following, have it checked
by your SUBARU dealer.
1. With the engine off, depress the brake
pedal several times, applying the same
pedal force each time. The distance the
pedal travels should not vary.
2. With the brake pedal depressed, start
the engine. The pedal should move
slightly down to the floor.
3. With the brake pedal depressed, stop
the engine and keep the pedal depressed
for 30 seconds. The pedal height should
not change.
4. Start the engine again and run for
approximately one minute then turn it off.
Depress the brake pedal several times to
check the brake booster. The brake
booster operates properly if the pedal
stroke decreases with each depression. NOTE
For vehicles equipped with the brake
assist system, when you depress the
brake pedal strongly or suddenly, you
might feel that lighter depression of the
brake pedal generates a greater brak-
ing force. However, even though these
occur, they do not indicate any mal- functions, and the brake assist system
is operating properly.
Brake assist is not a system that brings
more braking ability to the vehicle
beyond its breaking capability.
Brake pedal
Check the brake pedal free play and
reserve distance according to the main-
tenance schedule in the
“Warranty and
Maintenance Booklet ”.
& Checking the brake pedal
free play
1) 0.02 –0.08 in (0.5 –2.0 mm)
Stop the engine and firmly depress the
brake pedal several times. Lightly pull the
brake pedal up with one finger to check
the free play with a force of less than 2 lbf
(10 N, 1 kgf).
If the free play is not within proper
specification, contact your SUBARU deal-
er.

&Checking the brake pedal
reserve distance
1) More than 2.56 in (65 mm)
Depress the pedal with a force of approxi-
mately 66 lbf (294 N, 30 kgf) and measure
the distance between the upper surface of
the pedal pad and the floor.
When the measurement is smaller than
the specification, or when the pedal does
not operate smoothly, contact with your
SUBARU dealer. Clutch pedal
Check the clutch pedal free play and
reserve distance according to the main-
tenance schedule in the
“Warranty and
Maintenance Booklet ”.
& Checking the clutch function
Check the clutch engagement and disen-gagement.
1. With the engine idling, check that there
are no abnormal noises when the clutch
pedal is depressed, and that shifting into
1st or reverse feels smooth.
2. Start the vehicle by releasing the pedal
slowly to check that the engine and
transmission smoothly couple without
any sign of slippage. &
Checking the clutch pedal
free play1) 0.16 –0.43 in (4.0 –11.0 mm)
Lightly depress the clutch pedal down with
your finger until you feel resistance, and
check the free play.
If the free play is not within proper
specification, contact your SUBARU deal-
er. Maintenance and service
11-21

11-22Maintenance and service
Hill start assist system
Ensure that the Hill start assist system
operates properly under the followingcircumstances:
1. Stop the vehicle on an uphill grade by
depressing the brake pedal and clutch
pedal, with the engine running.
2. Make sure that the vehicle does not
move backward even after the brake
pedal is released.
3. Then make sure the vehicle starts
climbing the grade by following the normal
starting procedures.
If the Hill start assist system does not
operate as described above, contact with
your SUBARU dealer. Replacement of brake pad
and lining
The disc brakes have audible wear
indicators on the brake pads. If the brake
pads wear close to their service limit, the
wear indicator makes a very audible
scraping noise when the brake pedal isapplied.
If you hear this scraping noise each time
you apply the brake pedal, have the brake
pads serviced by your SUBARU dealer as
soon as possible.
CAUTION
If you continue to drive despite the
scraping noise from the audible
brake pad wear indicator, it will result in the need for costly brake
rotor repair or replacement.
& Breaking-in of new brake
pads and linings
When replacing the brake pad or lining,
use only genuine SUBARU parts. After
replacement, the new parts must be
broken in as follows. ! Brake pad and lining
While maintaining a speed of 30 to 40
mph (50 to 65 km/h), step on the brake
pedal lightly. Repeat this five or moretimes. ! Parking brake lining
1. Drive the vehicle at a speed of
approximately 22 mph (35 km/h).
2. With the parking brake release button
pushed in, pull the parking brake lever
SLOWLY and GENTLY (pulling with a
force of approximately 33.7 lbf [150 N,
15.3 kgf]).
3. Drive the vehicle for approximately
220 yards (200 meters) in this condition.
4. Wait 5 to 10 minutes for the parking
brake to cool down. Repeat this proce-dure.
5. Check the parking brake stroke. If the
parking brake stroke is out of the specified

Windshield washer fluid
If you spray washer fluid on the windshield
but the supply of washer fluid appears to
diminish, check the level of washer fluid in
the tank.
Washer fluid level gauge
Remove the washer tank filler cap, then
check the fluid level indicated by the level
gauge (attached to the inside of the cap).
If the level is near the“Low ”mark, add
fluid until it reaches the “Hi ”level on the level gauge or the
“FULL ”mark on the
tank.
Use windshield washer fluid. If windshield
washer fluid is unavailable use clean
water.
In areas where water freezes in winter,
use an anti-freeze type windshield washer
fluid. SUBARU Windshield Washer Fluid
contains 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
Concentration Freezing
Temperature
30% 10.48F( 12 8C)
50% 48F( 20 8C)
100% 49 8F( 45 8C)
CAUTION
Never use engine coolant as washer
fluid because it could cause paintdamage.
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 Maintenance and service
11-31
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11-38Maintenance and service
The other one (main fuse box) is housed
in the engine compartment.
The spare fuses are stored in the main
fuse box cover in the engine compart-ment.
The fuse puller is stored in the main fuse
box in the engine compartment.
1) Good
2) Blown
If any lights, accessories or other electrical
controls do not operate, inspect the corresponding fuse. If a fuse has blown,
replace it.
1. Turn the ignition switch to the
“LOCK ”
position and turn off all electrical acces- sories.
2. Remove the cover.
3. Determine which fuse may be blown.
Look at the back side of each fuse box
cover and refer to “Fuses and circuits ”
F 12-10.
4. Pull out the fuse with the fuse puller.
5. Inspect the fuse. If it has blown,
replace it with a spare fuse of the samerating.
6. If the same fuse blows again, this
indicates that its system has a problem.
Contact your SUBARU dealer for repairs.