When it comes to a diesel engine, you need to make sure that dirt is kept away because it is a deadly enemy. Dirt comes in many forms. Even though no one would deliberately put a handful of in their car’s engine, the truth of the matter is that you may be doing something very similar whenever you fill the fuel tank, add or change lubricants or just start the engine. This is where diesel oil filters come in. The filters do a more complicated job than you think.