1997 SUBARU LEGACY heating

TROUBLE
Engine will not start.
Rough idle and engine stall
Low output, hesitation and poor acceleration
Surging
Engine does not return to idle.
Dieseling (Run-on)
After burning in exhaust system
Knocking
Excessive engine oil consumption
Excessive fuel consumption Starter does not turn.
Initial combustion does not occur.
Initial combustion occurs.
Engine stalls after initial combustion.
LUBRICATION SYSTEM
22 3 3Incorrect oil pressure
2Loosened oil pump attaching bolts and defective
gasket
2Defective oil filter seal
2Defective crankshaft oil seal
32Defective rocker cover gasket
2Loosened oil drain plug or defective gasket
2Loosened oil pan fitting bolts or defective oil pan
COOLING SYSTEM
33221Overheating
333Over cooling
OTHERS
113 3Malfunction of Evaporative Emission Control
System
21Stuck or damaged throttle valve
322 2Accelerator cable out of adjustment
77
2-3DIAGNOSTICS
1. Engine Trouble in General

TROUBLE
Engine will not start.
Rough idle and engine stall
Low output, hesitation and poor acceleration
Surging
Engine does not return to idle.
Dieseling (Run-on)
After burning in exhaust system
Knocking
Excessive engine oil consumption
Excessive fuel consumption Starter does not turn.
Initial combustion does not occur.
Initial combustion occurs.
Engine stalls after initial combustion.
LUBRICATION SYSTEM
22 3 3Incorrect oil pressure
2Loosened oil pump attaching bolts and defective
gasket
2Defective oil filter seal
2Defective crankshaft oil seal
32Defective rocker cover gasket
2Loosened oil drain plug or defective gasket
2Loosened oil pan fitting bolts or defective oil pan
COOLING SYSTEM
33221Overheating
333Over cooling
OTHERS
113 3Malfunction of Evaporative Emission Control
System
21Stuck or damaged throttle valve
322 2Accelerator cable out of adjustment
79
2-3bDIAGNOSTICS
1. Engine Trouble in General

1. Engine Cooling System
Trouble Possible cause Corrective action
Over-heatinga. Insufficient engine coolantReplenish engine coolant, inspect for leakage, and
repair.
b. Loose timing belt Repair or replace timing belt tensioner.
c. Oil on drive belt Replace.
d. Malfunction of thermostat Replace.
e. Malfunction of engine coolant pump Replace.
f. Clogged engine coolant passage Clean.
g. Improper ignition timingInspect and repair ignition control system.

h. Clogged or leaking radiator Clean or repair, or replace.
i. Improper engine oil in engine coolant Replace engine coolant.
j. Air/fuel mixture ratio too leanInspect and repair fuel injection system.

k. Excessive back pressure in exhaust system Clean or replace.
l. Insufficient clearance between piston and cylinder Adjust or replace.
m. Slipping clutch Repair or replace.
n. Dragging brake Adjust.
o. Improper transmission oil Replace.
p. Defective thermostat Replace.
q. Malfunction of electric fanInspect radiator fan relay, engine coolant temperature
sensor or radiator motor and replace there.
Over-coolinga. Atmospheric temperature extremely low Partly cover radiator front area.
b. Defective thermostat Replace.
Engine coolant
leaks.a. Loosened or damaged connecting units on hoses Repair or replace.
b. Leakage from engine coolant pump Replace.
c. Leakage from engine coolant pipe Repair or replace.
d. Leakage around cylinder head gasket Retighten cylinder head bolts or replace gasket.
e. Damaged or cracked cylinder head and crankcase Repair or replace.
f. Damaged or cracked thermostat case Repair or replace.
g. Leakage from radiator Repair or replace.
Noisea. Defective drive belt Replace.
b. Defective radiator fan Replace.
c. Defective engine coolant pump bearing Replace engine coolant pump.
d. Defective engine coolant pump mechanical seal Replace engine coolant pump.
20
2-5DIAGNOSTICS
1. Engine Cooling System

1. Heater System
A: SPECIFICATIONS
Item Specifications Condition
Heating capacity4.652 kW (4,000 kcal/h, 15,872 BTU/h) or more ...
When 300 m
3(10,593 cu ft)/h
Mode
selector
switch: HEAT

Te m p .
control lever: FULL HOT

Temperature
difference
between hot
water and
inlet air:65°C (149°F)

Hot water
flow rate: 360
(95.1
US gal, 79.2
Imp gal)/h
Air flow rate 300 m
3(10,593 cu ft)/hHeat mode (FRESH), FULL
HOT at 12.5 V
Max air flow rate 510 m
3(18,008 cu ft)/h
Temperature
control lever: FULL COLD

Blower fan
speed: 4th position

RECIRC
switch
position: RECIRC
Heater core size
(height x length x width x
thickness)193.5 x 152.0 x 25.0 x 0.9 mm
(7.62 x 5.98 x 0.984 x 0.035 in)—
Blower
motorType Magnet motor 230 W or less at 12 V
Fan type and size
(diameter x width)Sirocco fan type
150 x 75 mm (5.91 x 2.95 in)—
2
4-6SPECIFICATIONS AND SERVICE DATA
1. Heater System

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

OBD0527
CT: DTC P1500
—RADIATOR FAN RELAY 1 CIRCUIT LOW
INPUT—
DTC DETECTING CONDITION:

Two consecutive driving cycles with fault
TROUBLE SYMPTOM:

Radiator fan does not operate properly.

Overheating
WIRING DIAGRAM:
B2M1289
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODE.

395
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostic Chart with Trouble Code for LHD Vehicles

OBD0538
CU: DTC P1502
—RADIATOR FAN FUNCTION PROBLEM—
DTC DETECTING CONDITION:

Two consecutive driving cycles with fault
TROUBLE SYMPTOM:

Occurrence of noise

Overheating
WIRING DIAGRAM:
B2M1290
401
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostic Chart with Trouble Code for LHD Vehicles

B2M1141
CW: DTC P1520
—RADIATOR FAN RELAY 1 CIRCUIT HIGH
INPUT—
DTC DETECTING CONDITION:

Two consecutive driving cycles with fault
TROUBLE SYMPTOM:

Radiator fan does not operate properly.

Overheating
WIRING DIAGRAM:
B2M1289
CAUTION:
After repair or replacement of faulty parts, conduct
CLEAR MEMORY and INSPECTION MODE.

405
2-7ON-BOARD DIAGNOSTICS II SYSTEM
10. Diagnostic Chart with Trouble Code for LHD Vehicles