Troubleshooting the cooling system (Mazda Capella GC)

Overheat

• Not enough coolant in the system (Section 1 and 3)
• Thermostat is faulty (Section 3)
• The radiator core is clogged (Section 3)
• The cooling fan or the thermal viscous coupling is faulty (Section 3)
• The expansion tank cap is damaged (Section 3)
• The timing belt is worn or not tensioned correctly (Section 2)
• The ignition timing is incorrectly adjusted (Section 1)
• The temperature sensor/indicator gives incorrect readings (Section 3)
• Air lock in the cooling system (Section 1)

Hypothermia

• Thermostat is faulty (Section 3)
• The temperature sensor/indicator gives incorrect readings (Section 3)

External coolant leak

• Hoses or their fastening clamps are worn or damaged (Section 1)
• The radiator core or heater matrix is leaking (Section 3)
• The expansion tank cap is damaged (Section 3)
• The water pump seal is leaking (Section 3)
• Boiling due to overheating (Section 3)
• The radiator cap is leaking (Section 3)

Internal coolant leak

• The cylinder head gasket is leaking (Section 2)
• The cylinder head or cylinder block is cracked (Section 2)

Corrosion

• Rare fluid replacement and system flushing (Section 1)
• Incorrect coolant mixture ratio or incorrect coolant type (Section 1)