The engine compartment is an often neglected area of the automobile, the regular washing and detailing of the car does not always include the engine compartment but it still needs to be cared for and cleaned to prevent deterioration of components and engine covers etc.
Modern engines are somewhat easier due to the large plastic engine covers used by many of the popular brands. The large cover needs to be washed and treated with a plastic conditioner and job done! Older classics require more attention due to the exposed nature of the engine bays in those days. Modern cars are very much designed to be weather proof so we do not need to concerned about getting the engine bay wet like we used to on older classics.