Table of contents: 43. Overheating ↓ 44. Hypothermia ↓ 45. External coolant leaks ↓ 46. Internal coolant leaks ↓ 47. There is a loss of coolant ↓ 48. Coolant circulation is disrupted ↓
43. Overheating
1. The coolant level has dropped.
2. The water pump drive belt is worn or damaged (with appropriate equipment), or its tension adjustment is broken.
3. The internal channels of the cooling system are blocked (including radiator), or as a result of blockage, the air flow through the heat exchanger of the air conditioning system is impaired.
4. The thermostat is stuck in the closed position.
5. The blades of the cooling system fan impeller are damaged.
6. The electric motor of the cooling system fan is faulty.
7. The ECT sensor is faulty.
8. The water pump is faulty.
9. The radiator/expansion tank cap does not hold pressure - check the cap valve under pressure.
44. Hypothermia
1. The thermostat is stuck in the open position.
2. Temperature meter readings are inaccurate.
45. External coolant leaks
1. The cooling system hoses are damaged or destroyed as a result of aging of the material, or their fastening on the fittings has become loose.
2. The water pump seals are damaged - coolant will leak through the inspection hole in the pump body.
3. There are leaks from the internal channels of the heat exchanger/side tank of the radiator.
4. There are leaks through the engine drain plug or the release plugs of the water galleries.
46. Internal coolant leaks
Note: Internal coolant leaks are usually detected by checking the engine oil. Inspect the dipstick blade for signs of moisture and oil foaming.
1. There are leaks through the cylinder head gasket - check the cooling system under pressure.
2. There are cracks in the cylinder walls or in the head casting.
47. There is a loss of coolant
1. There is too much coolant in the system.
2. The coolant boils away as a result of engine overheating.
3. There are internal or external coolant leaks (see sections 45 and 46).
4. Radiator/expansion tank cap is faulty - check cap valve under pressure.
48. Coolant circulation is disrupted
1. The water pump is not functioning properly. With the engine idling, pinch the upper radiator hose - if you feel a jolt of fluid inside the hose when you release it, the pump is functioning properly.
2. The cooling system is clogged. Drain the coolant (see Chapter 3), flush the system and fill it with fresh coolant. If necessary, remove the radiator and perform a reverse-flow flush.
3. The water pump drive belt is worn or damaged (with appropriate equipment) or its tension adjustment is impaired.
4. Thermostat is stuck.