| Symptom | Possible cause |
| Overheat | The coolant level in the system has dropped (see chapter Routine car maintenance). |
| The water pump drive belt is faulty or its tension adjustment is incorrect (see chapter Routine car maintenance). | |
| The radiator is blocked or its grille is obstructed (see chapter Cooling system). | |
| The thermostat is faulty (see chapter Cooling system). | |
| The radiator cap is damaged and does not hold pressure (see chapter Cooling system). | |
| The ignition timing angle setting is incorrect (see chapter Ignition system). | |
| Hypothermia | The thermostat is faulty (see chapter Cooling system). |
| There are external coolant leaks | The hoses are damaged mechanically or as a result of aging of the material, or their fastening with clamps has become loose (see Chapters Routine car maintenance and Cooling system). |
| The water pump seal is damaged (see Chapters Routine car maintenance and Cooling system). | |
| The radiator, heater heat exchanger or expansion tank is damaged (see chapter Cooling system). | |
| The radiator/cylinder block drain plugs are leaking, or the release plugs of the engine block water jacket are damaged (see Chapters Engine and Cooling system). | |
| There are internal coolant leaks | The cylinder head gasket is broken (see chapter Engine). The cylinder head or block is cracked (see chapter Engine). |
| Coolant losses occur | Too much fluid has been added to the system (see chapter Routine car maintenance). |
| The coolant boils away due to engine overheating. | |
| There are external or internal coolant leaks (see above). The radiator cap is faulty (see chapter Cooling system). | |
| Coolant circulation is disrupted | The water pump is faulty (see chapter Cooling system). |
| The cooling system is blocked (see Chapters Routine car maintenance and Cooling system). | |
| The water pump drive belt is faulty or its tension adjustment is incorrect (see chapter Routine car maintenance). | |
| The thermostat is stuck (see chapter Cooling system). |
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