Subaru Legacy 2003 Service Manual page 371

IGNITION
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.
SPARK PLUG
C: INSPECTION
Check electrodes and inner and outer porcelain of
plugs, noting the type of deposits and the degree of
electrode erosion.
IG-00049
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(H4SO)-6
( A )
( B )
( E )
(A) Electrode gap
(B) Carbon accumulation or wear
(C) Cracks
(D) Damage
(E) Damaged gasket
( C )
( D )
IG-00023
IG-00024
IG-00025