1997 SUBARU LEGACY spark plugs

G6M0088
2) Carbon fouled
Dry fluffy carbon deposits on insulator and electrode 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.
G6M0089
3) Oil fouled
Wet black deposits show excessive oil entrance into com-
bustion chamber through worn rings and pistons or exces-
sive clearance between valve guides and stems. If same
condition remains after repair, use a hotter plug.
G6M0090
4) Overheating
White or light gray insulator with black or gray brown spots
and bluish burnt electrodes indicate engine overheating.
Moreover, the appearance results 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.
G6M0091
C: CLEANING AND REGAPPING
Clean spark plugs in a sand blast type cleaner.
Avoid excessive blasting. Clean and remove carbon or
oxide deposits, but do not wear away porcelain.
If deposits are too stubborn, discard plugs.
After cleaning spark plugs, recondition firing surface of
electrodes with file. Then correct the spark plug gap using
a gap gauge.
Spark plug gap: L
1.0—1.1 mm (0.039—0.043 in)
D: REMOVAL AND INSTALLATION (2500 cc
EXCEPT OUTBACK MODEL)
CAUTION:
All spark plugs installed on an engine, must be of the
same heat range.
Spark plug:
NGK: PFR5B-11
24
6-1SERVICE PROCEDURE
3. Spark Plug

B6M0563A
6) Remove #4 spark plug cord by pulling boot, not cord
itself.
B6M0564
7) Remove spark plug with the spark plug socket.
8) Installation is in the reverse order of removal.
Tightening torque (Spark plug):
20.6±2.9 N⋅m (2.10±0.30 kg-m, 15.19±2.14 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-stressing.
E: REMOVAL (2500 cc OUTBACK MODEL)
CAUTION:
All spark plugs installed on an engine, must be of the
same heat range.
Spark plug:
NGK: PFR5B-11
G6M0095
1. #1 SPARK PLUG
1) Disconnect battery ground cable.
29
6-1SERVICE PROCEDURE
3. Spark Plug

B6M0574
6) Re-insert the tools disconnected in step 3) into plug
hole, and set them again over the spark plug.
7) Set extension and ratchet in turn onto the connected
tools in plug hole, and tighten spark plug to the specified
torque.
Tightening torque (spark plug):
20.6±2.9 N⋅m (2.10±0.30 kg-m, 15.19±2.14 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-stressing.
8) The subsequent procedures are in reverse order of #1
spark plug removal.
2. #2 SPARK PLUG
CAUTION:
When installing spark plug, cover the ATF cooling
pipes with a rag to prevent damage.
1) Carry out steps 1), 2), 3), 4), 6) and 7) of #1 spark plug
installation procedure.
2) Proceed in reverse order of #2 spark plug removal.

3. #3 SPARK PLUG
1) Carry out steps 1) through 7) of #1 spark plug installa-
tion procedure.
2) Proceed in reverse order of #3 spark plug removal.

4. #4 SPARK PLUG
CAUTION:
When installing spark plug, cover the ATF cooling
pipes with a rag to prevent damage.
1) Carry out steps 1), 2), 3), 4), 6) and 7) of #1 spark plug
installation procedure.
2) Proceed in reverse order of #4 spark plug removal.

35
6-1SERVICE PROCEDURE
3. Spark Plug

B: INSPECTION
1. BATTERY
1) External parts
Check for the existence of dirt or cracks on the battery
case, top cover, vent plugs, and terminal posts. If
necessary, clean with water and wipe with a dry cloth.
Apply a thin coat of grease on the terminal posts to prevent
corrosion.
2) Electrolyte level
Check the electrolyte level in each cell. If the level is below
MIN LEVEL, bring the level to MAX LEVEL by pouring dis-
tilled water into the battery cell. Do not fill beyond MAX
LEVEL.
WARNING:

Electrolyte has toxicity; be careful handling the
fluid.

Avoid contact with skin, eyes or clothing. Especially
at contact with eyes, blush with water for 15 minutes
and get prompt medical attention.

Batteries produce explosive gasses. Keep sparks,
flame, cigarettes away.

Ventilate when charging or using in enclosed space.

For safety, in case an explosion does occur, wear
eye protection or shield your eyes when working near
any battery. Never lean over a battery.

Do not let battery fluid contact eyes, skin, fabrics, or
paint-work because battery fluid is corrosive acid.

To lessen the risk of sparks, remove rings, metal
watch-bands, and other metal jewelry. Never allow
metal tools to contact the positive battery terminal and
anything connected to it while you are at the same time
in contact with any other metallic portion of the vehicle
because a short circuit will be caused.
5
6-2SERVICE PROCEDURE
2. Battery

10AI5
ONLY ONE CYLINDER
: Is there a fault in that cylinder?
NOTE:
Check the following items.

Spark plug

Spark plug cord

Fuel injector

Compression ratio
: Repair or replace faulty parts.
: Go to step10AI11.
10AI6
GROUP OF #1 AND #2 CYLINDERS
: Are there faults in #1 and #2 cylinders?
NOTE:

Check the following items.

Spark plugs

Fuel injectors

Ignition coil

If no abnormal is discovered, check for“D: IGNITION
CONTROL SYSTEM”of #1 and #2 cylinders side. 2-7 [T8D0].>
: Repair or replace faulty parts.
: Go to step10AI11.
216
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostic Chart with Trouble Code for LHD Vehicles

10AI7
GROUP OF #3 AND #4 CYLINDERS
: Are there faults in #3 and #4 cylinders?
NOTE:

Check the following items.

Spark plugs

Fuel injectors

Ignition coil

If no abnormal is discovered, check for“D: IGNITION
CONTROL SYSTEM”of #3 and #4 cylinders side. 2-7 [T8D0].>
: Repair or replace faulty parts.
: Go to step10AI11.
10AI8
GROUP OF #1 AND #3 CYLINDERS
: Are there faults in #1 and #3 cylinders?
NOTE:
Check the following items.

Spark plugs

Fuel injectors

Skipping timing belt teeth
: Repair or replace faulty parts.
: Go to step10AI11.
217
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostic Chart with Trouble Code for LHD Vehicles

10AI9
GROUP OF #2 AND #4 CYLINDERS
: Are there faults in #2 and #4 cylinders?
NOTE:
Check the following items.

Spark plugs

Fuel injectors

Skipping timing belt teeth
: Repair or replace faulty parts.
: Go to step10AI11.
10AI10
THE CYLINDER AT RANDOM
: Is the engine idle rough?
: Go to step10AI11.
: Go to DTC P0170. and [T10T5].>
B2M0759
10AI11
CHECK EGR SYSTEM.
: Is the minimum EGR system pressure value
(value of function mode (F42) less than 1
kPa?
NOTE:
Use the value read in step10X2for function mode F42.
: Clean EGR valve.
CAUTION:
Do not use solvent when cleaning EGR valve
assembly, as it can damage diaphragm.
NOTE:

Remove and blow away the exhaust deposits. Make
sure the valve operates smoothly and the valve seat area
is completely cleaned.

Replace EGR valve as required.
: Go to DTC P0170. and [T10T5].>
218
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostic Chart with Trouble Code for LHD Vehicles