Subaru Legacy (2005 year). Manual - part 414
CO(H6DO)-27
COOLING
Engine Cooling System Trouble in General
12.Engine Cooling System Trouble in General
A: INSPECTION
Trouble
Possible cause
Corrective action
Overheating
a. Insufficient engine coolant
Replenish engine coolant, inspect for leakage, and
repair it if necessary.
b. Defective thermostat
Replace.
c. Malfunction of water pump
Replace.
d. Clogged engine coolant passage
Clean.
e. Improper ignition timing
Inspect and repair the ignition control system. <Ref. to
EN(H6DO)(diag)-2, PROCEDURE, Basic Diagnostic
Procedure.>
f. Clogged or leaking radiator
Clean, repair or replace.
g. Improper engine oil in engine coolant
Check, repair or replace the parts around engine.
h. Air/fuel mixture ratio too lean
Inspect and repair the fuel injection system. <Ref. to
EN(H6DO)(diag)-2, PROCEDURE, Basic Diagnostic
Procedure.>
i. Excessive back pressure in exhaust system
Clean or replace.
j. Insufficient clearance between piston and cylinder
Adjust or replace.
k. Slipping clutch
Correct or replace.
l. Dragging brake
Adjust.
m. Faulty transmission gear oil
Replace.
n. Malfunction of radiator fan
Inspect radiator fan relay, engine coolant temperature
sensor or fan motor and replace them.
Over-cooling
a. Ambient temperature extremely low
Partly cover radiator front area.
b. Defective thermostat
Replace.
Engine coolant
leaks
a. Loosened or damaged connecting units on hoses
Correct or replace.
b. Leakage from water pump
Replace.
c. Leakage from water pipe
Correct or replace.
d. Leakage around cylinder head gasket
Retighten cylinder head bolts or replace gasket.
e. Damaged or cracked cylinder head and crankcase Correct or replace.
f. Damaged or cracked thermostat case
Correct or replace.
g. Leakage from radiator
Correct 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.