A car running at 80 km/hr produces at least 1,000 explosions per cylinder in the engine. These explosions are necessary; it's how the engine generates power to move the wheels. However, the downside is that the heat generated by these explosions will permanently damage your engine within minutes. Thus, cars have an automotive cooling system to regulate temperature in the engine.
There are two types of cooling systems fitted in motor vehicles: air-cooled (mostly used in motorcycles) and liquid-cooled. Older cars like the Volkswagen Beetle and Chevrolet Corvair were air-cooled. Modern vehicles use water-cooled systems, which is the focus of this article
Parts of a Car Cooling System
The following components comprise a water-cooled car cooling system:
- Thermostat – prevents the coolant from circulating when not required as it only activates after the engine reaches its standard operating temperature.
- Radiator – the heat exchanger, where the hot coolant is directed to cool off before it can be recirculated to the engine to continue its work. Without the radiator, your car would require several litres of coolant each day.
- Radiator cap (or pressure cap) – maintains the pressure in the system.
- Water pump – it sends back the coolant from the radiator to the engine. A damaged water pump can cause engine failure. One symptom of a faulty pump are strange noises coming from the engine and specifically the driver's side.
- Radiator fans – mounted on the back of the radiator; they keep air flowing in the engine when temperatures go above 1100C and when the car slows down or comes to a stop.
- Head gasket or intake manifold gasket – the head gasket works as a seal to prevent the coolant from leaking into the cylinders; some engines use intake manifold gaskets, which have the same function as the head gasket.
- Hoses – the pipes through which the coolant circulates the engine.
- Coolant – the primary cooling element in the system; it can handle up to 2,500C without boiling. Its ethylene glycol component prevents it from freezing when temperatures go sub-zero.
How the Automotive Cooling System Works
The automotive cooling system works by passing liquid coolant through the passages in the engine to dissipate heat. First, the thermostat is activated when the car reaches its optimum operating temperature. The coolant then flows through the engine block, cooling it by absorbing heat as it moves and ending up in the radiator to cool. It then flows back to the engine to repeat the cycle all over again.
When the thermostat senses that the coolant's temperature is below a certain level, its valve remains closed, allowing the coolant to bypass the radiator and, in turn, diverts it back to the engine.
The system is pressurised to prevent the coolant from reaching the boiling point. However, pressure does build up sometimes, and this may result in damaged gaskets and hoses. The radiator cap (or pressure cap) releases excess pressure and excess fluid, which is stored and cooled in a reserve tank. The cooled fluid is then recirculated to the system.
Maintenance and Repair of the Car Cooling System
The automotive cooling system needs proper maintenance and repair. A damaged water pump will be incapable of pumping the coolant throughout the engine’s passages as it should and cause the engine to overheat at some point.
When the thermostat is damaged, it will record incorrect temperatures and cause the release of hot coolant back to the engine, which defeats the purpose of a coolant.
Whenever you notice a problem in the car cooling system, it is best to replace these parts immediately. Hoses, gaskets, thermostat, and even radiators, are so much cheaper to replace than the engine, so never delay repairs and replacement of parts. Read more about the radiator and maintenance tips for the cooling system.
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By Eric Anyega