Oil cooler

An oil cooler is a small radiator through which engine oil is pumped and cooled by the airflow. Oil carries heat away from hot spots such as pistons, bearings and the cylinder head, so cooling it helps the whole engine. Oil coolers are common on air-cooled and air-and-oil-cooled engines and on high-performance bikes; some liquid-cooled engines use an oil-to-water heat exchanger instead.

Many coolers have a thermostat that bypasses the cooler until the oil is warm, because oil that is too cold does not protect well either.

Keep the fins clean, straighten bent ones gently and check hoses and fittings for cracks or seepage. A mesh guard is a good idea on off-road and adventure bikes, where stones can puncture the core.