2011 SUBARU IMPREZA WRX spark plugs

Maintenance schedule....................................... 11-3
Maintenance precautions ................................... 11-3
Before checking or servicing in the engine compartment .................................................... 11-4
When checking or servicing in the engine compartment .................................................... 11-4
When checking or servicing in the engine compartment while the engine is running .......... 11-5
Engine hood ....................................................... 11-5
Engine compartment overview .......................... 11-7
Non-turbo models .............................................. 11-7
Turbo models except STI .................................... 11-8
STI..................................................................... 11-9
Engine oil .......................................................... 11-10
Checking the oil level ....................................... 11-10
Changing the oil and oil filter ............................ 11-11
Recommended grade and viscosity .................. 11-13
Synthetic oil ..................................................... 11-13
Cooling system ................................................ 11-13
Cooling fan, hose and connections ................... 11-14
Engine coolant ................................................. 11-14
Air cleaner element .......................................... 11-17
Replacing the air cleaner element ..................... 11-17
Spark plugs ...................................................... 11-19
Recommended spark plugs .............................. 11-20
Drive belts ........................................................ 11-20
Manual transmission oil .................................. 11-21
Checking the oil level ....................................... 11-21
Recommended grade and viscosity .................. 11-21Automatic transmission fluid
.......................... 11-22
Checking the fluid level .................................... 11-22
Recommended fluid ......................................... 11-23
Front differential gear oil (AT models) ........... 11-23
Checking the oil level ...................................... 11-23
Recommended grade and viscosity .................. 11-24
Rear differential gear oil .................................. 11-24
Recommended grade and viscosity .................. 11-24
Power steering fluid ........................................ 11-24
Checking the fluid level .................................... 11-24
Recommended fluid ......................................... 11-25
Brake fluid ........................................................ 11-25
Checking the fluid level .................................... 11-25
Recommended brake fluid ............................... 11-26
Clutch fluid (MT models) ................................. 11-26
Checking the fluid level .................................... 11-26
Recommended clutch fluid ............................... 11-27
Brake booster .................................................. 11-27
Brake pedal ...................................................... 11-28
Checking the brake pedal free play .................. 11-28
Checking the brake pedal reserve distance....... 11-28
Clutch pedal (MT models) ............................... 11-29
Checking the clutch function ............................ 11-29
Checking the clutch pedal free play .................. 11-29
Hill start assist system (MT models –if
equipped) ...................................................... 11-29
Replacement of brake pad and lining ............ 11-30
Breaking-in of new brake pads and linings ....... 11-30
Parking brake stroke ....................................... 11-31
Maintenance and service
11

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.
4. Open the air cleaner case and remove
the air cleaner element.
5. Clean the inside of the air cleaner case
and case cover with a damp cloth and
install a new air cleaner element.
6. If the air cleaner case has been
removed, insert the three projections on
the air cleaner case into the slits on the air
cleaner case cover.
7. Install in the reverse order of removal.Spark plugs
It may be difficult to replace the spark
plugs. It is recommended that you have
the spark plugs replaced by your
SUBARU dealer.
The spark plugs should be replaced
according to the maintenance schedule
in the
“Warranty and Maintenance Book-
let ”.
CAUTION
. When disconnecting the spark
plug cables, always grasp the
spark plug cap, not the cables.
. Make sure the cables are re-
placed in the correct order. Maintenance and service
11-19
– CONTINUED –

11-20Maintenance and service
&Recommended spark plugs
For the recommended spark plugs, refer to “Electrical system ”F 12-3. 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.

&Engine
Engine model EJ253
(2.5 L, SOHC, non-turbo) EJ255
(2.5 L, DOHC, turbo, except STI) EJ257
(2.5 L, DOHC, turbo, STI)
Engine type Horizontally opposed, liquid cooled 4 cylinder, 4-stroke gasoline engine
Displacement cc (cu-in) 2,457 (150)
Bore 6Stroke in (mm) 3.963.1 (99.5 679.0)
Compression ratio 10.0 : 1 8.4 : 1 8.2 : 1
Firing order 1
–3 –2–4
& Electrical system
Battery type and capacity (5HR) MT 12V-48AH (55D23L)
AT 12V-52AH (65D23L)
Alternator Non-turbo models 12V-90A
Turbo models 12V-110A
Spark plugs Non-turbo models FR5AP-11 (NGK)
Turbo models SILFR6A (NGK)
AT: Automatic transmission
MT: Manual transmission Specifications
12-3
– CONTINUED –

14-8Index
P Parking Brake ................................................................... 7-40
Brake stroke ......................................................... 11-31
Tips...................................................................... 7-40
Periodic inspections ..................................................... 8-4
Petrol fuel ................................................................... 7-3
Power Door locking switch .................................................. 2-6
Outside mirrors .............................................. 3-47, 3-48
Steering ................................................................ 7-31
Steering fluid ................................................ 11-24, 12-9
Windows ............................................................... 2-21
Precautions against vehicle modification ............... 1-21, 1-57
Preparing to drive ........................................................ 7-8
R Rear Combination lights ................................................. 11-51
Differential gear oil ........................................ 11-24, 12-8
Gate ............................................................. 2-27, 9-18
Turn signal light .................................................... 11-51
Viscous limited slip differential ................................. 7-30
Rear differential
Oil temperature warning light ................................... 3-19
Rear seat .................................................................... 1-7
Armrest ................................................................... 1-8
Folding down ........................................................... 1-9
Head restraint adjustment ......................................... 1-8
Rear window
Defogger ............................................................... 3-48 Wiper and washer switch
......................................... 3-39
Wiper blades ........................................................ 11-42
Recommended
Automatic transmission fluid ..................................... 12-9
Brake fluid ............................................................. 12-9
Clutch fluid ............................................................ 12-9
Engine oil .............................................................. 12-5
Front differential gear oil .......................................... 12-8
Manual transmission oil ........................................... 12-8
Power steering fluid ................................................ 12-9
Rear differential gear oil .......................................... 12-8
Spark plugs ........................................................... 12-3
Refueling .................................................................... 7-4
Remote engine start system ........................................ 7-11
Remote keyless entry system ....................................... 2-8
Replacement
Brake pad and lining ............................................. 11-30
Wiper blades ........................................................ 11-39
Replacing Air cleaner element ............................................... 11-17
Battery (remote engine start transmitter) .................... 7-13
Battery (remote keyless entry system) ....................... 2-11
Lost transmitters (remote keyless entry system) ......... 2-12
Replacing bulbs ....................................................... 11-47
Back-up light (4-door) ............................................ 11-51
Back-up light (5-door) ............................................ 11-52
Brake/Tail and rear side marker light (4-door) ........... 11-51
Cargo area light ................................................... 11-54
Dome light ........................................................... 11-54
Front fog light ....................................................... 11-50
Front turn signal light ............................................ 11-50

Headlight............................................................. 11-47
High mount stop light ............................................. 11-55
License plate light ................................................. 11-53
Map light .............................................................. 11-53
Rear combination light ........................................... 11-51
Trunk light ............................................................ 11-55
REV indicator light and buzzer ..................................... 3-11
Rocking the vehicle .................................................... 8-11
Roof molding and crossbar ......................................... 8-14
S Safety Precautions when driving ............................................. 5
Symbol ...................................................................... 2
Warnings ................................................................... 2
Seat Fabric ................................................................... 10-5
Front ...................................................................... 1-2
Heater .................................................................... 1-6
Rear ....................................................................... 1-7
Seatbelt ................................................................. 5, 1-11
Fastening .............................................................. 1-12
Maintenance .......................................................... 1-19
Pretensioners ........................................................ 1-19
Safety tips ............................................................. 1-11
Warning light and chime ......................................... 3-14
Security Alarm system ........................................................ 2-16
ID plate ................................................................... 2-3
Immobilizer. ............................................................. 2-2
Indicator light ......................................................... 3-25 Shock sensors
....................................................... 2-20
Select lever ............................................................... 7-23
Position indicator .................................................... 3-26
Shift lock function ................................................... 7-24
Shift-up indicator light .................................................. 3-26
Shock sensors ........................................................... 2-20
Shopping bag hook ..................................................... 6-11
SI-DRIVE Indicator light ......................................................... 3-26
SI-DRIVE mode. ......................................................... 7-28
Snow tires ....................................................... 8-10, 11-31
Snowy and icy roads ................................................... 8-9
Sounding a panic alarm .............................................. 2-10
Spark plugs ..................................................... 11-19, 12-3
Specifications ............................................................. 12-2
Speedometer .............................................................. 3-8
SPORT mode ............................................................ 7-28
Indicator light ......................................................... 3-25
SRS Curtain airbag ........................................................ 1-49
Frontal airbag ......................................................... 1-39
Side airbag ............................................................ 1-49
SRS airbag (Supplemental Restraint System airbag)... 5, 1-35
SRS airbag system Monitors ................................................................ 1-55
Servicing ............................................................... 1-57
Warning light .......................................................... 3-15
Starting the engine ...................................................... 7-9
State emission testing (U.S. only) .................................. 7-7
Steering wheel Power ................................................................... 7-31 Index
14-9