Car engine cooling system parts

Cooling for your car: find out more! Which ones to choose, when to change them, and how much they cost

An engine cooling system helps to keep the engine from overheating and thus keep its elements from harm. In modern vehicles, it carries heat away from hot engine components and warms air in the heater. It can also cool oil, exhaust gases, turbocharged air, and the transmission fluid in automatic gearboxes.

Design of engine cooling systems

An engine cooling system consists of the following elements:

• Coolant expansion tank. This is a reservoir for storing coolant. It is designed to compensate for coolant volume changes. The tank cap has a special valve used to regulate the pressure level in the cooling system.
• Water pump. It ensures coolant circulation.
• Radiator. This component is used to cool antifreeze. The fluid flow moves through thin pipes connected to metal fins for heat dissipation. Counter-current airflows pass between the fins, thus cooling the pipes and the fluid inside of them.
• Fan. It produces additional airflow when the engine requires more intense cooling.
• Thermostat. This component regulates the flow of fluid inside the system. When the engine is started when it’s cold, the valve of the thermostat is closed. The coolant moves along the small circuit without passing through the radiator. As soon as the engine reaches its operating temperature, the valve opens and the fluid starts flowing along the big circuit, including the radiator.
• Hoses. These are used to connect components of an engine cooling system.
• Sensors. These are used to control the system. For example, for switching the fan on automatically.

Maintenance tips

• Only use high-quality coolant. Replace it on time. Old fluid may be contaminated with byproducts of wear and corrosion of the pump, as well as particles of damaged sealing elements.
• Flush the cooling system when you change the coolant. Clean fluff, leaves, and sticky dirt from the outer part of the radiator every time you perform routine maintenance on the system. You may wash it with running water but not under pressure, as you might otherwise damage the radiator fins.
• Do not drive with a low level of coolant. This may cause the engine to overheat.
• Always remove airlocks from the engine cooling system.
• Immediately replace cracked, deformed, or hardened hoses with new ones. Don’t wait until they start leaking.
• Always observe the mixing ratio specified by the coolant manufacturer when diluting the coolant with water. The more water you add to the coolant, the higher its freezing point will be.

Signs of malfunction

Engine overheating can indicate such malfunctions. Defects of the engine cooling system such as a clogged radiator, a stuck thermostat valve, and a faulty pump impeller can be indicated by engine overheating. Sometimes, the engine may need more time to warm up to its operating temperature. This can be a symptom of the thermostat failure as well. If you notice a puddle (usually of green colour) beneath your car after parking for a prolonged time, this can be a sign of hoses cracked on account of the radiator corroding. A rapidly decreasing level of coolant in the expansion tank is another sign of leaks in the assemblies.

Сauses of malfunction

Hoses and pipes are subjected to normal wear and tear; they lose their elasticity and crack. Temperature fluctuations have a destructive effect on them. Sometimes these parts may become damaged when carrying out repairs or maintenance in the engine compartment. The radiator can easily be damaged by careless cleaning. Clogging might be a result of improper or frequent use of sealants and other additives. The systems which comprise both metal and aluminium parts are more prone to corrosion. Try not to combine such metal types in the same system.

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Useful information on functions, causes of malfunction, diagnosis and replacement intervals

• Car Thermostat: how it works and replacement costs