An engine oil cooler works as a heat exchanger. It circulates the engine oil through a series of passages or tubes, allowing the heat to dissipate as it does so.
There are 2 main types of engine oil coolers:
Air-cooled oil coolers: Air-cooled oil coolers rely on ambient air to dissipate heat
They use the same working principle that a radiator uses;
hot oil flows through some tubes with fins that join them. Those fins lower the fluid temperature. Cooled by liquid: In this type of coolers there flows oil and coolant.