Cooling system malfunctions

Poor heat radiation

Water pump malfunction

Drive belt looseness or wear

—

Thermostat or water control valve is stuck closed.

—

Damage of radiator fins

Clogging by mud or foreign substance

Physical damage

Clogged radiator hose

Foreign substance intrusion (corrosion, mud, sand, etc.)

Reduced cooling airflow

Cooling fan does not operate

Cooling fan assembly

—

Poor cooling fan rotation

Damage of cooling fan

Damage of radiator shroud

—

—

—

Incorrect LLC concentration

—

—

—

Deteriorated coolant

—

LLC concentration

—

Low coolant level

Coolant leakage

Radiator hose

Loose hose clamps

Cracks and fractures of hose

Water pump

Poor seal

Radiator cap

Looseness

Poor seal

Radiator

Damage, deterioration, or poor installation of O-ring

Cracks and fractures of radiator tank

Cracks and fractures of radiator core

Reservoir tank

Cracking of reservoir tank cap

Overflow of coolant from the reservoir tank

Entry of combustion gas into the cooling system

Cylinder head distortion

Deterioration of cylinder head gasket

Malfunction other than the cooling system

—

Engine overload

High-load driving

High engine speed with no load

Driving in low gear for a long period of time

Extreme continuous high-speed driving

Power train system malfunction

—

Size of installed wheel or tire

Dragging of brakes

Ignition timing

Obstruction of outside air inflow

Blocked bumper opening

—

—

Blocked radiator grille

Installation of bumper cover

Blocked by mud or foreign substance

Clogged radiator fins

—

Clogged condenser fan

Obstruction of outside air inflow path

Blocked due to installation of fog lamps