Subaru Legacy III (2000-2003 year). Manual - part 90

IG(H4SO)-4

IGNITION

GENERAL DESCRIPTION

C: CAUTION

• Wear working clothing, including a cap, protec-
tive goggles, and protective shoes during opera-
tion.
• Remove contamination including dirt and corro-
sion before removal, installation or disassembly.
• Keep the disassembled parts in order and pro-
tect them from dust or dirt.
• Before removal, installation or disassembly, be
sure to clarify the failure. Avoid unnecessary re-
moval, installation, disassembly, and replacement.
• Be careful not to burn your hands, because each
part on the vehicle is hot after running.
• Be sure to tighten fasteners including bolts and
nuts to the specified torque.
• Place shop jacks or safety stands at the specified
points.
• Before disconnecting electrical connectors of
sensors or units, be sure to disconnect ground ca-
ble from battery.

IG(H4SO)-5

IGNITION

SPARK PLUG

2. Spark Plug

A: REMOVAL

CAUTION:
All spark plugs installed on an engine, must be 
of the same heat range.

Spark plug:

CHAMPION: RC10YC4

(Alternate)

NGK: BKR5E-11
NGK: BKR6E-11

1. RH SIDE

1) Disconnect battery ground cable.

2) Remove resonator chamber.
<Ref. to IN(H4SO)-8, REMOVAL, Resonator
Chamber.>
3) Remove spark plug cords by pulling boot, not
cord itself.

4) Remove spark plugs with the spark plug socket.

2. LH SIDE

1) Disconnect battery ground cable.

2) Disconnect washer motor connector.

3) Disconnect rear window glass washer hose from
washer motor, then plug connection with a suitable
cap.
4) Remove the two bolts which hold the washer
tank, then take the tank away from the working ar-
ea.

5) Remove spark plugs cord by pulling boot, not
cord itself.

FU-00009

IG-00046

IG-00047

FU-00009

IG-00019

IG-00020

IG-00048

IG(H4SO)-6

IGNITION

SPARK PLUG

6) Remove spark plug with the spark plugs socket.

B: INSTALLATION

1. RH SIDE

1) Install in the reverse order of removal.

Tightening torque (Spark plug):

21 N·m (2.1 kgf-m, 15 ft-lb)

CAUTION:
The above torque should be only applied to 
new spark plugs without oil on their threads.
In case their threads are lubricated, the torque
should be reduced by approximately 1/3 of the
specified torque in order to avoid over-stress-
ing.

Tightening torque (Resonator chamber):

33 N·m (3.4 kgf-m, 24.6 ft-lb)

2. LH SIDE

1) Install in the reverse order of removal.

Tightening torque (Spark plug):

21 N·m (2.1 kgf-m, 15 ft-lb)

CAUTION:
The above torque should be only applied to 
new spark plugs without oil on their threads.
In case their threads are lubricated, the torque
should be reduced by approximately 1/3 of the
specified torque in order to avoid over-stress-
ing.

C: INSPECTION

Check electrodes and inner and outer porcelain of
plugs, noting the type of deposits and the degree of
electrode erosion.

1) Normal
Brown to grayish-tan deposits and slight electrode
wear indicate correct spark plug heat range.

2) Carbon fouled
Dry fluffy carbon deposits on insulator and elec-
trode are mostly caused by slow speed driving in
city, weak ignition, too rich fuel mixture, dirty air
cleaner, etc.
It is advisable to replace with plugs having hotter
heat range.

IG-00049

(A) Electrode gap

(B) Carbon accumulation or wear

(C) Cracks

(D) Damage

(E) Damaged gasket

IG-00023

( A )

( B )

( C )

( E )

( D )

IG-00024

IG-00025

IG(H4SO)-7

IGNITION

SPARK PLUG

3) Oil fouled
Wet black deposits show excessive oil entrance
into combustion chamber through worn rings and
pistons or excessive clearance between valve
guides and stems. If same condition remains after
repair, use a hotter plug.

4) Overheating
White or light gray insulator with black or gray
brown spots and bluish burnt electrodes indicate
engine overheating. Moreover, the appearance re-
sults from incorrect ignition timing, loose spark
plugs, wrong selection of fuel, hotter range plug,
etc. It is advisable to replace with plugs having
colder heat range.

D: CLEANING

Clean spark plugs in a sand blast type cleaner.
Avoid excessive blasting. Clean and remove car-
bon or oxide deposits, but do not wear away porce-
lain.
If deposits are too stubborn, replace plugs.

E: ADJUSTMENT

Correct it if the spark plug gap is measured with a
gap gauge, and it is necessary.

Spark plug gap: L

1.0 — 1.1 mm (0.039 — 0.043 in)

NOTE:
Replace with new spark plug if this area is worn to
“ball” (A) shape.

IG-00026

IG-00027

IG-00028

L

( A )