Diagnostics and troubleshooting of the cooling system (Mercedes-Benz E-Class W124)

Engine overheating

• Insufficient fluid level in the cooling system.
• The thermostat is not working.
• The internal cavities of the radiator are clogged.
• The radiator fan or the thermoviscous coupling is faulty.
• The temperature gauge sensor or temperature gauge does not display the temperature correctly.
• The presence of an air lock in the cooling system.
• The expansion tank cap is damaged.

The engine does not warm up

• Thermostat is faulty.
• The temperature gauge sensor or temperature gauge does not display the temperature correctly.
• The thermoviscous coupling is faulty.

External coolant leaks

• The cooling system hoses or hose clamps are damaged.
• The radiator or heater core is leaking.
• The expansion tank cap is faulty.
• The water pump sealing ring is leaking.
• The gasket installed between the water pump and the cylinder block is leaking.
• Liquid boiling when the engine overheats.
• The radiator cap is leaking.

Internal coolant leaks

• The cylinder head gasket is blown.
• Cracks in the cylinder head or cylinder block.

Corrosion of cooling system elements

• Periodic replacement of coolant or flushing of the cooling system was not performed.
• Using water in the cooling system or improper ratio of antifreeze concentrate to distilled water when preparing the coolant.

[Material taken from a web resource: mercedesman.ru]