2012 SUBARU IMPREZA WRX engine

Specifications..................................................... 12-2
Dimensions ........................................................ 12-2
Engine ............................................................... 12-3
Electrical system ................................................ 12-3
Fuel ................................................................... 12-4
Lubricants. ......................................................... 12-5
Fluids ................................................................ 12-7
Engine coolant ................................................... 12-8 Tires
.................................................................. 12-9
Fuses and circuits ........................................... 12-10
Fuse panel located in the passenger compartment ................................................. 12-10
Fuse panel located in the engine compartment ................................................. 12-12
Bulb chart ......................................................... 12-14
Vehicle identification ....................................... 12-17Specifications
12

&Engine
Engine model 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 8.4 : 18.2 : 1
Firing order 1
– 3–2– 4
& Electrical system
Battery type and capacity (5HR) MT 12V-48AH (55D23L)
Alternator Turbo models
12V-110A
Spark plugs Turbo models
SILFR6A (NGK)Specifications
12-3
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12-4Specifications
&Fuel
NOTE
The engine is designed to operate using unleaded gasoline.
Model Fuel requirement Fuel tank capacity
Except STI 91 AKI (95 RON) or higher*
1
16.9 US gal (64 liters, 14.1 Imp gal)
STI 93 AKI (98 RON) or higher*2
*1: If unleaded gasoline with an octane rating of 91 AKI (95 RON) is not available, unleaded gasoline with an octane rating of 87 AKI (90 RON) or higher
may be temporarily used. For details, refer to
“Fuel ”F 7-3.
*2: If unleaded gasoline with an octane rating of 93 AKI (98 RON) is not available, unleaded gasoline with an octane rating of 91 AKI (95 RON) may be
used with no detriment to engine durability or driveability. For details, refer to “Fuel ”F 7-3.

&Lubricants
NOTE
Each quantity indicated here is only a guideline. The necessary quantity for replacement may differ slightly depending on the
temperature and other factors. ! Engine oil
For checking, adding and replacing procedure, or other details, refer to “Engine oil ”F 11-8.
Oil grade SAE viscosity No. and
applicable temperature Engine oil capacity
API classification SM or SN
with the words “
ENERGY CONSERVING ”or
“ RESOURCE CONSERVING ”orILSAC GF-4 or GF-5, which can be
identified with the ILSAC certification
mark (Starburst mark) 5W-30 synthetic
oil is the required oil for
optimum engine performance and pro-
tection. Conventional oil may be used if
synthetic oil is unavailable.
*: 10W-30, 10W-40, 5W-30 or 5W-40
conventional oil may be used if replen-
ishment is needed but should be changed
to 5W-30 synthetic oil at the next oil change.
· When adding the oil from L to F level:
1.1 US qt (1.0 liter, 0.9
Imp qt)
· When changing the oil and oil filter:
- Except STI:
4.4 US qt (4.2 liters, 3.7
Imp qt)
- STI:
4.5 US qt (4.3 liters, 3.8
Imp qt) Specifications
12-5
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12-8Specifications
&Engine coolant
NOTE
Each quantity indicated here is only a guideline. The necessary quantity for replacement may differ slightly depending on the
temperature and other factors.
Model Coolant capacity Coolant type
Turbo models Except STI 7.8 US qt (7.4 liters, 6.5 Imp qt)
SUBARU Super Coolant
STI 8.1 US qt (7.7 liters, 6.8 Imp qt)
For the checking, adding and replacing procedure, or other details, refer to “Cooling system ”F 11-11.

12-10Specifications
Fuses and circuits &Fuse panel located in the passenger compartmentFuse
panel Fuse
rating Circuit
1 Empty 2 Empty
3 15A .Door locking
4 10A .Front wiper deicer relay
5 10A .Combination meter
. Clock
6 7.5A .Remote control rear
view mirrors
. Seat heater relay
7 15A .Combination meter
. Integrated unit
8 20A .Stop light
9 15A .Front wiper deicer
10 7.5A .Power supply (battery)
11 7.5A .Turn signal unit
12 15A .Engine control unit
. Integrated unit
13 20A .Accessory power outlet
(center console)
14 15A .Position light
. Tail light
. Rear combination light
15 Empty

12-12Specifications
&Fuse panel located in the engine compartment
A) Main fuse Fuse
panel Fuse
rating Circuit
1 30A .ABS unit
. Vehicle Dynamics Con-
trol unit
2 25A .Main fan (cooling fan)
3 10A .Secondary air combina-
tion valve (turbo models)
4 25A .Sub fan (cooling fan)
5 Empty
6 10A .Audio
7 30A .Headlight (low beam)
8 15A .Headlight (high beam)
9 20A .Back-up
10 15A .Horn
11 25A .Rear window defogger
. Mirror heater
12 15A .Fuel pump
13 10A .Automatic transmission
control unit
14 7.5A .Engine control unit
15 15A .Turn and hazard warn-
ing flasher
16 15A .Tail and illumination re-
lay
17 7.5A .Alternator

crease in temperature could cause
tread separation, and failure of the
tire(s). Possible resulting loss of
vehicle control could lead to anaccident. !Measuring and adjusting air
pressure to achieve proper in-
flation
Check and, if necessary, adjust the
pressure of each tire (including the
spare) at least once a month and
before any long journey. Check the
tire pressures when the tires are
cold. Use a pressure gauge to
adjust the tire pressures to the
specific values. Driving even a
short distance warms up the tires
and increases the tire pressures.
Also, the tire pressures are affected
by the outside temperature. It is
best to check tire pressure out-
doors before driving the vehicle.
When a tire becomes warm, the air
inside it expands, causing the tire
pressure to increase. Be careful not
to mistakenly release air from a
warm tire to reduce its pressure. &
Glossary of tire terminology
. Accessory weight
The combined weight (in excess of
those standard items which may be
replaced) of automatic transmis-
sion, power steering, power brakes,
power windows, power seats, radio,
and heater, to the extent that these
items are available as factory-in-
stalled equipment (whether in-
stalled or not). . Bead
The part of the tire that is made of
steel wires, wrapped or reinforced
by ply cords and that is shaped to fit
the rim.. Bead separation
A breakdown of the bond between
components in the bead.. Bias ply tire
A pneumatic tire in which the ply
cords that extend to the beads are
laid at alternate angles substantially
less than 90 degrees to the center-
line of the tread. . Carcass
The tire structure, except tread and sidewall rubber which, when in-
flated, bears the load. .
Chunking
The breaking away of pieces of the
tread or sidewall.. Cold tire pressure
The pressure in a tire that has been
driven less than 1 mile or has been
standing for three hours or more.. Cord
The strands forming the plies in the tire. . Cord separation
The parting of cords from adjacent
rubber compounds.. Cracking
Any parting within the tread, side-
wall, or inner liner of the tire
extending to cord material. . Curb weight
The weight of a motor vehicle with
standard equipment including the
maximum capacity of fuel, oil and
coolant, and if so equipped, air
conditioning and additional weight
optional engine.
Consumer information and Reporting safety defects
13-5
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