Keeping the engine compartment clean , for me anyways, has always been a two fold benefit. When you lift the hood to show guys with modified Mustangs that they got whipped so bad by a basically stock engine, cleanliness can be your friend. When something goes wrong and repairs are needed, a clean engine compartment is it's own reward. It can also prevent critters from moving in and rust from forming. Cleaning the car brings you into "oneness" with the vehicle as well, you learn where stuff is, how it's supposed to look,and grow closer to your ride. Just my opinion. Can you tell I miss my 2000 Ram Air?