Cooling system troubleshooting (Renault Clio 1)

Overheat

• Insufficient amount of coolant in the system ("Weekly checks").
• Thermostat is faulty (Section 3).
• The radiator core or grille is blocked (Section 3).
• The electric fan or thermal switch is faulty (Section 3).
• Inaccurate temperature sensor or indicator on the panel (Section 3).
• Air lock in the cooling system (Section 3).
• The cap on the expansion tank is faulty (Section 3).

Hypothermia

• Thermostat is faulty (Section 3).
• Inaccurate temperature sensor or indicator on the panel (Section 3).

Coolant leaking outward

• The hoses are damaged or the clamps that secure them are loose (Section 1).
• Leaky radiator or heater pipes (Section 3).
• The radiator cap is damaged (Section 3).
• Destruction of the water pump cuff (Section 3).
• Leaky gasket between water pump and cylinder block (Section 3).
• Boiling due to overheating (Section 3).
• Leakage of the block plug (Section 2).

(This article is taken from the website: RENAULTBOOK.ru)

Coolant leaking inside

(usually in the oil pan)

• Cylinder head gasket leakage (Section 2).
• Crack in the cylinder head or block (Section 2).

Corrosion

• Infrequent draining of fluid and flushing of the system (Section 1).
• Poor quality coolant or the wrong type of coolant (Section 1).