● Types of Cooling
● Key Components of the Cooling System
Coolant
As the medium that carries heat away from the engine, coolant plays a crucial role in the entire cooling system. The quality of the coolant directly determines the effectiveness of the system’s cooling capability.
Engine coolant is composed of ethylene glycol, corrosion inhibitors, anti-foaming agents, and water. Ethylene glycol is a key component that expands the liquid's operational temperature range. When mixed with water, the coolant can remain stable without boiling or freezing within a range of approximately 200°C to -60°C. The higher the concentration of the coolant, the more expensive it is, but in reality, not all regions require highly concentrated coolant. Therefore, manufacturers produce coolant with varying concentrations based on regional conditions. The different colors of coolant are due to added dyes, which make it easier to detect leaks.
Auxiliary Cooling
To help the engine cool down faster, you can turn on the heater. The heater core, mentioned earlier when introducing components of the cooling system, normally serves as the heat source for the car’s heater. However, as part of the cooling system, it can also function as an auxiliary radiator. The hot air blown by the heater can assist in lowering the engine temperature.
Whistling Sound
The coolant reservoir is typically used to store coolant, but during summer high temperatures when poor engine cooling causes the coolant to expand from the heat, it also serves as a pressure relief mechanism. The cap of the coolant reservoir is equipped with a pressure relief valve. When the pressure inside the cooling system becomes excessively high, the valve opens automatically to release internal pressure. At this point, you may hear the sound of pressurized air escaping through the valve—a phenomenon commonly referred to as “whistling.”
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