3-84 ENGINE AND ENGINE Of ERHAUL
Troubleshooting the Cooling System
Problem Cause SolutionCoolant loss—boilover Faulty rfead gasket
Cracke^l head, manifold, or block
Faulty rtfidiator capReplace head gasket
Replace as necessary
Replace capCoolant entry into crankcase or
cylinder(s)Faulty rjiead gasket
Crack in head, manifold or blockReplace head gasket
Replace as necessaryCoolant recovery system inoperative Coolan level low
Leak mjsystemPressu e cap not tight or seal
miss ig, or leaking
Pressu e cap defective
Overflc N tube clogged or leaking
Recov^ ry bottle vent restrictedReplenish coolant to FULL mark
Pressure test to isolate leak and
repair as necessary
Repair as necessaryReplace cap
Repair as necessary
Remove restrictionNoise Fan contacting shroudLoose jjvater pump impeller
Glazed fan belt
Loose an belt
Rough surface on drive pulley
Water pump bearing wornBelt alignmentReposition shroud and inspect
engine mounts
(on electric fans inspect assembly)
Replace pump
Apply silicone or replace belt
Adjust fan belt tension
Replace pulley
Remove belt to isolate. Replace
pump.
Check pulley alignment. Repair as
necessary.
No coolant flow through heater core Restri
pump
Heate
Restri
Restri
housirjjg
Intake
cylmd
Faulty
Intake
restnc:ed return inlet in waterhose collapsed or restricted
ted heater core
ted outlet in thermostat
3
nanifold bypass hole in
r head restricted
heater control valve
manifold coolant passage
•dRemove restrictionRemove restriction or replace hose
Remove restriction or replace core
Remove flash or restrictionRemove restrictionReplace valve
Remove restriction or replace
intake manifold
NOTE: Immediately after shutdown, the engine
system being inoperative while engine tempe,
expansion and pressure may push some coo/a
is considered normal.•n(ers a condition known as heat soak. This is caused by the cooling
iture is still high. If coolant temperature rises above boiling point,
t out of the radiator overflow tube. If this does not occur frequently it