Cooling System Theory
The correct function of the cooling system is critical. The thermal management needs have evolved since the days of air cooled engines. Modern engineering pushes the boundaries of performance and relies more than ever on cooling system theory.
The air cooled engine has one major cooling flaw. It lacks a thermal buffer. It needs to dissipate heat immediately. Otherwise, it overheats. It needs to be cooled off every time it is worked hard. This is too idealistic for everyday applications.
Heat created by the explosion inside the engine is mostly evacuated through the exhaust. But there are metal surfaces that absorb heat. Cooling off the walls of the combustion chamber and the cylinder head is the main task of the cooling system.
Using a liquid to absorb heat is the most convenient. It allows an easy transfer towards a holding tank. There, it has time to be cooled off before it repeats the cycle. Another benefit over air cooled engine is the larger and purpose built surface area for cooling. The radiator is designed specifically to dissipate heat. Its fin density and materials are ideal for transferring heat to the air.
The coolant volume has a certain thermal capacity. It absorbs heat each time it passes through the engine. The radiator competes to cool it back off for the next cycle. For greatest efficiency, the temperature difference has to be as large as possible.
In comparison to air cooled engines, water-cooling seems to solve many issues. However, it simply pushes the boundaries to be less noticeable. There are still limitations. For example, the amount of air passed through the radiator or the boiling point of the coolant.
There are tricks to push the boundary further. One is to increase the coolant volume by installing a larger radiator. Another is increasing the airflow through the radiator with a more aggressive cooling fan controller. The very last step could be to spin the waterpump faster, however, in most cases, this is not a good idea.