Subaru Legacy III (2000-2003 year). Manual - part 445
CO(H4DOSTC)-34
COOLING
ENGINE COOLING SYSTEM TROUBLE IN GENERAL
13.Engine Cooling System Trouble in General
A: INSPECTION
Trouble
Corrective action
Over-heating
a. Insufficient engine coolant
Replenish 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 water pump
Replace.
f. Clogged engine coolant passage
Clean.
g. Improper ignition timing
Inspect and repair ignition control system.
<Ref. to EN(H4DOSTC)-2, ENGINE, PROCEDURE,
Basic Diagnostic Procedure.>
h. Clogged or leaking radiator
Clean or repair, or replace.
i. Engine oil mixed in engine coolant
Replace engine coolant.
j. Air/fuel mixture ratio too lean
Inspect and repair fuel injection system.
<Ref. to EN(H4DOSTC)-2, ENGINE, PROCEDURE,
Basic Diagnostic Procedure.>
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. Malfunction of electric fan
Inspect radiator fan relay, engine coolant temperature
sensor or radiator motor and replace there.
Over-cooling
a. Atmospheric temperature extremely low
Partly cover radiator front area.
b. Malfunction of thermostat
Replace.
Engine coolant
leaks.
a. Loosened or damaged connecting units on hoses
Repair or replace.
b. Leakage from water pump
Replace.
c. Leakage from water 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.
Noise
a. Defective drive belt
Replace.
b. Defective radiator fan
Replace.
c. Defective water pump bearing
Replace water pump.
d. Defective water pump mechanical seal
Replace water pump.