Subaru Legacy 2003 Service Manual page 1819

IGNITION
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.
SPARK PLUG
2. LH SIDE
1) Install in the reverse order of removal.
Tightening torque (Spark plug):
Tightening torque (Ignition coil):
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
IG-00007
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.
IG-00008
1) Normal:
IG-00009
Brown to grayish-tan deposits and slight electrode
wear indicates correct spark plug heat range.
IG(H4DOSTC)-6
21 N·m (2.1 kgf-m, 15.2 ft-lb)
16 N·m (1.6 kgf-m, 11.7 ft-lb)
( A )
( B )
( E )
(A) Electrode gap
(B) Carbon accumulation or wear
(C) Cracks
(D) Damage
(E) Damaged gasket
( C )
( D )
IG-00010
IG-00011