The purpose of the camshaft oil cooler is to remove heat. The oil is drained from the oil in the two-stroke crosshead engine into a separate tank from the camshaft body through hydraulic exhaust valves. With a pump from the oil tank, the camshaft oil is passed through the cooler and filter and sent to the system. Preheating can be done by the circulation of auxiliary engine cooling water in order not to keep the engine during shorter departures at the port. Preheated water can come to the heat exchanger via a separate circulation pump.