Subaru Legacy III (2000-2003 year). Manual - part 452

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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 the ground
cable from battery.

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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:

NGK: PFR6G

1. RH SIDE

1) Disconnect the ground cable from battery.

2) Remove the air cleaner lower case. <Ref. to
IN(H4DOSTC)-10, REMOVAL, Air Cleaner.>
3) Disconnect the connector from ignition coil.

4) Remove the ignition coil.

5) Remove the spark plugs with the spark plug
sockets.

2. LH SIDE

1) Disconnect the battery cables, and then remove
the battery and battery carrier.

2) Disconnect the washer motor connector.

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

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IGNITION

SPARK PLUG

5) Disconnect the connector from ignition coil.

6) Remove the ignition coil.

7) Remove the spark plugs with the spark plug
sockets.

B: INSTALLATION

1. RH SIDE

1) Install in the reverse order of removal.

Tightening torque (Spark plug):

21 N·m (2.1 kgf-m, 15.2 ft-lb)

Tightening torque (Ignition coil):

16 N·m (1.6 kgf-m, 11.7 ft-lb)

NOTE:
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 approx. 1/3 of the specified
torque in order to avoid over-stressing.

2. LH SIDE

1) Install in the reverse order of removal.

Tightening torque (Spark plug):

21 N·m (2.1 kgf-m, 15.2 ft-lb)

Tightening torque (Ignition coil):

16 N·m (1.6 kgf-m, 11.7 ft-lb)

NOTE:
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 approx. 1/3 of the specified
torque in order to avoid over-stressing.

C: INSPECTION

Check the 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 indicates correct spark plug heat range.

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(A) Electrode gap

(B) Carbon accumulation or wear

(C) Cracks

(D) Damage

(E) Damaged gasket

( A )

( B )

( C )

( D )

( E )

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IGNITION

SPARK PLUG

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.

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 the 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 indicates
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: ADJUSTMENT

Clean the spark plugs with a wire brush. Clean and
remove the carbon or oxide deposits, but do not
wear away porcelain.
If deposits are too stubborn, replace the plugs. 
After cleaning the spark plugs, correct the spark
plug gap using a gap gauge.

NOTE:
Do not use spark plug cleaners, because the spark
plugs are applied with platinum tips.

Spark plug gap: L

0.7 — 0.8 mm (0.028 — 0.031 in)

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

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L

( A )