Ricardo 4105 Oil Cooler   An oil cooler is a smaller radiator that works to maintain a consistent and optimal temperature for the engine’s oil supply. It helps to dissipate heat from the oil, which in turn helps to prolong the life of the engine and transmission. Oil coolers are often necessary for diesel engines and automatic gearboxes, which operate at higher temperatures. This particular oil cooler is an aftermarket part for a John Deere tractor. Errors & Omissions Excepted (E&EO