The Engine Cooling system

The automotive cooling system is one of the most important systems among the various systems. it helps regulate the engine working temperature at the normal working temperature. Because the engine produces a lot of heat and the temperature becomes too high that it can damage the engine if  not regulated that's why the cooling system is needed to regulate the temperature.

 There are two types of cooling system, which is the air cooling system and the liquid cooling system.

Air cooled system.

 The air cooled system is not commonly used on modern cars, only on some more bikes and older cars like the Volkswagen beetle and some others.
Frequently a duct runs all around the fins, and an engine-driven fan blows air through the duct to take heat away from the fins.
A temperature-sensitive valve controls the amount of air being pushed around by the fan, and keeps the temperature constant even on cold days.

The Liquid Cooled System.

 It's what you will find on almost all cars.
Basically the liquid cooling system works by circulating the coolant liquid in the engine to carry the heat and give it off through the radiator. the system comprises of the coolant fluid, the radiator that serves as the heat exchanger, the pump that drives out the hot coolant out of the engine and pumps in the cooled fluid from the radiator, the thermostat to regulate the temperature, and the hoses that connects the radiator and the engine, heater core, and the water channels/gallery running through the engine and the cylinder top .

 In a liquid cooled engine, the engine block and the cylinder top have interconnected coolant channels running through them. and the channels converges at one point on the cylinder where it's been connected to the radiator
 through a hose.

How the liquid cooling system works.

 As earlier stated the cooling system works by circulating the coolant fluid through the engine and the radiator.

[The coolant fluid is a poisonous fluid which is a mixture of water and antifreeze (ethylene glycol) at 50/50 ratio. the coolant is a fluid that can withstand engine temperature as high as 250° without boiling and bellow 0° without freezing. the fluid contains rust inhibitors and lubricant.]

 The coolant fluid flows through the channels in the engine block and cylinder top to pick up the heat, and then to the radiator through a hose at the cylinder top. The hot fluid gets into the radiator and it's being cooled by the air stream passing through the radiator core.
[The radiator has fan that blows air through it cores. the fan can be electrically powered or by the engine powered fan that is rotated by the crankshaft through a belt.]

 The cooled fluid returns into the engine block channels to pick up more heat. the circulation continues by the help of the pump driven by a pulley and a belt connected to the engine's crankshaft. The pump keeps driving out the hot fluid to the radiator and brings in the cooled fluid into the engine.

 Between the radiator and engine connection is a thermostat that helps keep the engine working at the right temperature. For an engine to deliver it's optimum performance it has to be at a specific temperature range. This is what the thermostat helps to accomplish.

 If the coolant temperature becomes lower than the preset temperature, the thermostat closes it's valve to block the flow from going into the radiator, instead it returns the fluid to the engine through a bypass. And when heated up enough to a certain temperature it opens the valve to allow the flow into the radiator.
In order to prevent the coolant fluid from boiling, the cooling system is pressurised. under pressure the boiling point is raised considerably.
Due to the expansion of fluids with increased temperature.
In order to prevent excess pressure that is caused by this phenomenon that may cause the hoses or other pipes to burst. The work is done by the radiator cap which is designed to open it's valve at a specific pressure. When the pressure become too much the valve opens letting the fluid to be discharged into an expansion tank that stores up the fluid until the pressure goes down, and the fluid is being sucked up back into the system.

 The heater core helps keep the interior warm on cold days. the hot coolant helps provide the heat when needed.
the heater core looks like a radiator but it's more simpler and smaller. two hoses connects to the core, one brings in the hot coolant and exits through the other hose. there's an electric fan that blows air through the core to provide the hot air for the interior.
the heater core has a control valve that restricts the flow of hot fluid. when warm air is not needed in the interior.


Images source; howcarswork. Com