Swap out the dirty factory air filter in your 1994-1998 Dodge 5.9L Diesel with a high-quality Drop-In Air Filter. Drop-in air filters are aptly named as they have a "drop-in" installation that allows them to fit inside of your factory air box. Most factory-style drop-in air filters are made with a paper filter media, and aftermarket performance air filters generally use a cotton-gauze media that requires filter oil, or a synthetic dry media. Find drop-in filters from manufacturers like S&B Filters, AFE, K&N Engineering, and others at XDP. Air Filters provide your engine with clean air by trapping harmful contaminants such as dust and debris before entering the intake.