Overheating Cause AnalysisNBLC0029
Symptom Check items
Cooling sys-
tem parts
malfunctionPoor heat transferWater pump malfunction Worn or loose drive belt
Ð Thermostat stuck closed Ð
Damaged finsDust contamination or
paper clogging
Mechanical damage
Clogged radiator cooling
tubeExcess foreign material
(rust, dirt, sand, etc.)
Reduced air flowCooling fan does not oper-
ate
ÐÐ High resistance to fan rota-
tion
Damaged fan blades
Damaged radiator shroud Ð Ð Ð
Improper coolant mixture
ratioÐÐÐ
Poor coolant quality Ð Ð Ð
Insufficient coolantCoolant leaksCooling hoseLoose clamp
Cracked hose
Water pump Poor sealing
Radiator capLoose
Poor sealing
RadiatorO-ring for damage, dete-
rioration or improper fit-
ting
Cracked radiator tank
Cracked radiator core
Reservoir tank Cracked reservoir tank
Overflowing reservoir tankExhaust gas leaks into
cooling systemCylinder head deteriora-
tion
Cylinder head gasket
deterioration
ENGINE COOLING SYSTEM
Overheating Cause Analysis
LC-24
Symptom Check items
Except cool-
ing system
parts mal-
functionÐ Overload on engineAbusive drivingHigh engine rpm under
no load
Driving in low gear for
extended time
Driving at extremely high
speed
Powertrain system malfunc-
tion
Ð Installed improper size
wheels and tires
Dragging brakes
Improper ignition timing
Blocked or restricted air
flowBlocked bumper Ð
Ð Blocked radiator grilleInstalled car brassiere
Mud contamination or
paper clogging
Blocked radiator Ð
Blocked condenser
Ð
Installed large fog lamp
Service Data and Specifications (SDS)
THERMOSTATNBLC0030
Valve opening temperature76.5ÉC (170ÉF)
Valve liftMore than 8.6 mm/90ÉC (0.339 in/194ÉF)
WATER CONTROL VALVENBLC0035
Valve opening temperature95ÉC (203ÉF)
Valve liftMore than 8.0 mm/108ÉC (0.315 in/226ÉF)
RADIATORNBLC0031Unit: kPa (kg/cm2, psi)
Cap relief pressureStandard 78 - 98 (0.8 - 1.0, 11 - 14)
Limit 59 - 98 (0.6 - 1.0,9-14)
Leakage test pressure157 (1.6, 23)
GI
MA
EM
EC
FE
AT
TF
PD
AX
SU
BR
ST
RS
BT
HA
SC
EL
IDX
ENGINE COOLING SYSTEM
Overheating Cause Analysis (Cont'd)
LC-25
