1. Insufficient coolant level in the cooling system (see «Checking the technical condition of the cooling system»).
2. Malfunction of the coolant pump (see «Coolant pump - replacement»).
3. The radiator of the engine cooling system is clogged (see «Radiator of the engine cooling system - removal and installation»).
4. Faulty thermostat (see «Checking the technical condition of the cooling system»),
5. Faulty electric fan of the engine cooling system (see «Electric fan - removal, disassembly and installation»).
6. Faulty valves in the cap of the expansion tank (replace cap).