The function of the oil cooler is to cool the lubricating oil and keep the oil temperature within the normal working range. On high-power reinforced engines, oil coolers must be installed because of the large heat load. When the engine is running, the lubrication ability is reduced because the oil viscosity becomes thinner with the increase of temperature. Therefore, some engines are equipped with oil coolers, whose function is to reduce the oil temperature and maintain a certain viscosity of the lubricating oil. The oil cooler is arranged in the circulating oil circuit of the lubrication system.

The engine oil cooler is divided into water-cooled and air-cooled, and the air-cooled oil cooler core is composed of many cooling tubes and cooling plates. When the car is driving, the hot oil cooler core is cooled by the car's head-on wind. Air-cooled oil coolers require good ventilation around, and it is difficult to ensure sufficient ventilation space on ordinary cars, which is generally rarely used. This kind of cooler is mostly used in racing cars, because the racing speed is high and the cooling air volume is large. The water-cooled type is that the oil cooler is placed in the cooling waterway, and the temperature of the cooling water is used to control the temperature of the lubricating oil. When the temperature of the lubricating oil is high, it is cooled by the cooling water, and when the engine starts, the heat is absorbed from the cooling water to rapidly increase the temperature of the lubricating oil.

The oil cooler is made of aluminum alloy shell, front cover, back cover and copper core tube. In order to enhance the cooling, the tube is equipped with heat sink. The cooling water flows outside the pipe, the lubricating oil flows inside the pipe, and the two exchange heat. There are also structures that cause oil to flow outside the pipe and water to flow inside.