Troubleshooting - Subaru XT 1988 Service Manual

2-5
ENGINE COOLING SYSTEM
TROUBLESHOOTING
Trouble Possible cause Corrective action
Over-heating
a.
I nsufficient coolant. Replenish coolant, inspect for leakage, and
repair.
b.
Loose drive belt. Adjust drive belt tension.
c. Oil on drive belt. Replace.
d. Malfunction of thermostat. Replace.
e. Malfunction of water pump.
Repair or replace.
f. Clogged coolant passage. Clean.
g. Improper ignition timing. Adjust.
h.
Clogged or leaking radiator. Clean or repair, or replace.
i.
Improper engine oil. Replace.
j.
Air-fuel mixture too thin. Inspect and repair fuel system.
k. Excessive back pressure in exhaust system, Clean or replace.
I. Insufficient clearance between piston and Adjust or replace.
cylinder.
m. Improper valve clearance. Adjust.
n. Slipping clutch.
Repair or replace.
o.
Dragging brake. Adjust.
p.
Improper transmission oil.
Replace.
q.
Defective thermostat.
Replace.
r.
Malfunction of electric fan. Replace thermoswitch or motor.
Over-cooling
a.
Atmospheric temperature extremely low. Partly cover radiator front area.
b.
Defective thermostat, Replace.
Coolant leaks
a.
Loosened or damaged connecting units on Repair or replace.
hoses.
b.
Leakage from water pump. Repair or replace.
c. Leakage from intake manifold. Repair or replace.
d. Leakage around cylinder head gasket. Retighten cylinder head nuts or replace gasket.
e.
Damaged or cracked cylinder head and Repair or replace.
crankcase.
f. Damaged or cracked thermostat case, Repair or replace.
g. Leakage from radiator. Repair or replace.
Noise
a. Defective drive belt.
Replace.
b. Defective electric fan.
Replace.
c. Defective water pump bearing.
Replace.
d. Defective water pump mechanical seal.
Replace.
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