Subaru 1600 Service Manual page 120

ENGINE
2. Cooling System
Trouble
Over-heating
Over-cooling
Coolant leaks
Noise
Possible cause
a. Insufficient coolant.
b. Loose drive belt.
c. Oil on drive belt.
d. Malfunction of thermostat.
e. Malfunction of water pump.
f.
Clogged coolant passage.
g. Improper ignition timing.
h. Clogged or leaking radiator.
i.
Improper engine oil.
j.
Air-fuel mixture too thin.
k. Excessive back pressure in exhaust
system.
I.
Insufficient clearance between piston
and cylinder.
m. Improper valve clearance.
n. Slipping clutch.
o. Dragging brake.
p. Improper transmission oil.
q. Defective thermostat.
r. Malfunction of electric fan.
a. Outside temperature extremely low.
b. Defective thermostat.
a. Loosened or damaged connecting units
on hoses.
b. Leakage from water pump.
c. Leakage from thermo valve.
d. Leakage from intake manifold.
e. Leakage around cylinder head gasket.
f.
Damaged or cracked cylinder head and
crankcase.
g. Damaged or cracked thermostat case.
h. Leakage from radiator.
a. Defective drive belt.
b. Defective electric fan.
c. Defective water pump bearing.
d. Defective water pump mechanical seal.
Corrective action
Replenish coolant, inspect for leakage, and
repair.
Adjust drive belt tension.
Replace.
Replace.
Repair or replace.
Clean.
Adjust.
Clean or repair, or replace.
Replace.
Inspect and repair fuel system.
Clean or replace.
Adjust or replace.
Adjust.
Repair or replace.
Adjust.
Replace.
Replace.
Replace.
Partly cover radiator front area.
Replace.
Repair or replace.
Repair or replace.
Replace.
Repair or replace.
Retighten cylinder head nuts or replace
gasket.
Repair or replace.
Repair or replace.
Repair or replace.
Replace.
Replace.
Replace.
Replace.