2003 SUBARU IMPREZA spark plugs

11
11-1
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Maintenance schedule 11-3 . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Maintenance precautions 11-3 . . . . . . . . . . . . . . . . . . . . . . . .
Engine hood 11-5 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Engine compartment overview 11-8 . . . . . . . . . . . . . . . . .
2.5 liter model 11-8 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2.0 liter (Turbo) model 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 . . . . . . . . . . .
Recommended grade and viscosity under
severe driving conditions 11-15 . . . . . . . . . . . . . . . . . . . . . .
Synthetic oil 11-15
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Cooling system 11-15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Cooling fan, hose and connections 11-16 . . . . . . . . . . . .
Engine coolant 11-16 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Air cleaner element 11-20 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Replacing the air cleaner element 11-20 . . . . . . . . . . . . . .
Spark plugs 11-23 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Recommended spark plugs 11-24 . . . . . . . . . . . . . . . . . . . . .
Drive belts 11-24 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Manual transmission oil 11-25 . . . . . . . . . . . . . . . . . . . . . . . . . .
Checking the oil level 11-25 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Recommended grade and viscosity 11-26 . . . . . . . . . . .
Automatic transmission fluid 11-27 . . . . . . . . . . . . . . . . . . .
Checking the fluid level 11-27 . . . . . . . . . . . . . . . . . . . . . . . . . .
Recommended fluid 11-29 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Front differential gear oil (AT vehicles) 11-29
. . . . .
Checking the oil level 11-29 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Recommended grade and viscosity 11-30 . . . . . . . . . . .
Rear differential gear oil 11-31 . . . . . . . . . . . . . . . . . . . . . . . . . .
Checking the gear oil level 11-31 . . . . . . . . . . . . . . . . . . . . . . .
Recommended grade and viscosity 11-32 . . . . . . . . . . .
Power steering fluid 11-32 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Checking the fluid level 11-32 . . . . . . . . . . . . . . . . . . . . . . . . . .
Recommended fluid 11-33 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Brake fluid 11-34 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Checking the fluid level 11-34 . . . . . . . . . . . . . . . . . . . . . . . . . .
Recommended brake fluid 11-34 . . . . . . . . . . . . . . . . . . . . . . .
Clutch fluid (MT vehicles) 11-35 . . . . . . . . . . . . . . . . . . . . . . . .
Checking the fluid level 11-35 . . . . . . . . . . . . . . . . . . . . . . . . . .
Recommended clutch fluid 11-36 . . . . . . . . . . . . . . . . . . . . . .
Brake booster 11-36 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Brake pedal 11-37 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Checking the brake pedal free play 11-37 . . . . . . . . . . . .
Checking the brake pedal reserve distance 11-37 . .
Clutch pedal (MT vehicles) 11-38 . . . . . . . . . . . . . . . . . . . . . .
Checking the clutch function 11-38 . . . . . . . . . . . . . . . . . . . .
Checking the clutch pedal free play 11-38 . . . . . . . . . . .
Replacement of brake pad and lining 11-39 . . . . . . . .
Breaking-in of new brake pads and linings 11-39 . . .
Parking brake stroke 11-40 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tires and wheels 11-41 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Types of tires 11-41 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Maintenance and service

Maintenance and service
11-23
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4. To install the air cleaner case cover, insert the two
projections on the air cleaner case cover into theslits on the air cleaner case and then snap the two
clamps on the air cleaner case cover. Spark plugs
It may be difficult to replace the spark plugs. It is
recommended that you have the spark plugs re-
placed by your SUBARU dealer.
The spark plugs should be replaced according to
the maintenance schedule in the
“Warranty and
Maintenance Booklet ”.

Maintenance and service
11-24
CAUTION
When disconnecting the spark plug cables,
always grasp the spark plug cap, not the cables. Make sure the cables are replaced in the
correct order.
Recommended spark plugs
Non-turbo models: RC10YC4 (Champion) BKR6E-11 (NGK)
BKR5E-11 (NGK)
Turbo models: PFR6G (NGK)
Drive belts
1) Power steering pump pulley
2) Air conditioner compressor pulley
3) Crank pulley
The alternator, power steering pump, and air condi-
tioner compressor depend on drive belts. Satisfacto-
ry performance requires that belt tension be correct.
To check belt tension, place a straightedge (ruler)
across two adjacent pulleys and apply a force of 22 lb (98 N, 10 kg) midway between the pulleys by us- ing a spring scale. Belt deflection should be the
amount specified. If a belt is loose, cracked, or

Specifications
12-3
– CONTINUED –
Engine
Engine model
EJ251
(2.5-liter, SOHC, non-turbo)EJ205
(2.0-liter, DOHC, turbo)
Engine typeHorizontally opposed, liquid cooled 4 cylinder, 4-stroke gasoline engine
Displacement cu in. (cc)150 (2,457)122 (1,994)
Bore × Stroke in. (mm)3.9 × 3.1 (99.5 × 79.0)3.6 × 2.9 (92.0 × 75.0)
Compression ratio10.0 : 18.0 : 1
Firing order1 – 3 – 2 – 4
Electrical system
Battery type and
it (5HR)MT12V-48AH (55D23L)capacity (5HR)ATWith 2.5-liter engine12V-52AH (75D23L)
With 2.0-liter turbo engine12V-52AH (65D23L)
Alternator2.5-liter engine12V – 75A
2.0-liter turbo engine12V – 75A
Spark plugs2.5-liter engineRC10YC4 (Champion)
BKR6E-11 (NGK)
BKR5E-11 (NGK)
2.0-liter turbo enginePFR6G (NGK)
AT : Automatic transmission MT : Manual transmission

Index
14-7
Spark plugs 11-24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Remote keyless entry system 2-6 . . . . . . . . . . . . . . . . .
Replacement Brake pad and lining 11-39 . . . . . . . . . . . . . . . . . . . . . . . .
Windshield wiper blades 11-50 . . . . . . . . . . . . . . . . . . .
Replacing bulbs 11-61 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Cargo area light 11-73 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Doom light 11-73 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Front fog light 11-68 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Front turn signal light 11-64 . . . . . . . . . . . . . . . . . . . . . . . .
Front side marker light 11-69 . . . . . . . . . . . . . . . . . . . . . .
Headlight 11-62 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
High mount stop light 11-74 . . . . . . . . . . . . . . . . . . . . . . .
License plate light 11-72 . . . . . . . . . . . . . . . . . . . . . . . . . . .
Map light 11-73 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Parking light 11-64 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Rear combination light 11-70 . . . . . . . . . . . . . . . . . . . . . .
Trunk light 11-74 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Replacing
Lost transmitters (keyless entry system) 2-10 . .
Air cleaner element 11-20 . . . . . . . . . . . . . . . . . . . . . . . . .
Battery (remote keyless entry system) 2-8 . . . . .
Rocking the vehicle 8-15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Roof rail and crossbar 8-18 . . . . . . . . . . . . . . . . . . . . . . . . .
S Seatbelt 6
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Maintenance 1-27
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pretensioners 1-27 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Safety tips 1-12 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Warning light and chime 1-15, 3-10 . . . . . . . . . . . . . . .
Seatbelts 1-12
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Seat Cushion height adjustment (driver ’s seat) 1-5 .
Fabric 10-5
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Heater 1-6
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Security system 2-14 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Selector lever 7-15 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Shift lock release 7-19 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Shift position indicator 3-15 . . . . . . . . . . . . . . . . . . . . . . . . .
Side ventilators 4-3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Snow tires 8-13
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Sounding a panic alarm 2-8, 2-17 . . . . . . . . . . . . . . . . . . .
Spark plugs 11-23 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Specifications 12-2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Speedometer 3-6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SRS airbag (Supplemental Restraint System airbag) 6, 1-42 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SRS airbag system warning light 3-11 . . . . . . . . . . . . . .
SRS frontal airbag 1-46 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SRS side airbag 1-55 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Starting the engine 7-9 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
State emission testing (U.S. only) 7-6 . . . . . . . . . . . . . . . .
Stopping the engine 7-11 . . . . . . . . . . . . . . . . . . . . . . . . . . . .