Vehicles that use internal combustion engines work by igniting fuel inside the combustion chambers in the engine. This generates a large amount of heat which can damage the metal by melting it and causing it to fuse with other components. If this were to occur, the engine becomes essentially useless and would require partial or complete replacement. In order to avoid this situation, the engine needs to be cooled as the vehicle is running.
An engine oil cooler serves this purpose by running oil through the hot components of the engine and cycling it through the engine along all the components that are likely to generate heat and transfer this heat away through the oil. This circulation allows the engine to remain cool, and the heat to be transferred to the air around the engine and out of the vehicle. The oil acts as a medium through which the heat travels from the components to the air. Since warm substances are less dense, hot oil would flow through to the radiator and cool off. As the oil cools, it becomes denser and flows back into the engine components and the cycle repeats as the engine runs.
The oil used as a coolant in modern combustion engine is known as ‘engine oil’ and has several properties that make it well suited for this application. The oil is less viscous, and has high thermal capacity, which allows it to carry more heat per unit volume. The oil is circulated around the engine through tubes and pipes which have a high conductivity to heat and then cooled in the radiator with moving cool air from the external environment. The tubing exposed to the air is made to have higher surface area to maximise the area of contact with the air and increase cooling capacity.
There are also several types of engine coolers. The most popular being an oil to air engine cooler, which cools the engine elements using the oil and then cools the oil using airflow from the radiator. Another type is oil to water engine coolers, which make use of a heat exchanger to cool the oil using the water. The water is then cooled using air similar to the former type. This allows the transfer of more heat energy per unit time and is therefore suitable for more powerful engines. In general, the more powerful the engine, the more powerful the cooler that should be used, as powerful engines generate more heat.
An engine oil cooler cools the primary functional components of the engine and prevents it from overheating. The presence of a functional cooler extends the lifetime of the engine and protects it against excessive wear. However, they can be difficult to install and maintain, with the positioning being an important factor in its function. It is generally recommended to obtain the services of a professional to perform maintenance tasks on the cooling system and radiator as improper function can damage the vehicle substantially.