WIX Filters - Heavy Duty Fuel Filters - Products - Product It is also good to remember that the primary fuel filter for any diesel engine should always be a fuel/water separator. All diesel fuel contains some water, and removing it ensures longer diesel injection system life and productive engine uptime. This is why WIX fuel filters WIX Filters - Light Duty Fuel Filters - Products - Product A high-quality WIX fuel filter is essential for protecting advanced fuel injection systems from contaminants that may be in the fuel, allowing an engine to run trouble free and at peak mile-per-gallon performance. All of the fuel that enters the engine must first pass through the fuel filter. wix diesel fuel filter | eBay Find great deals on eBay for wix diesel fuel filter. Shop with confidence. Skip to main content. eBay Logo: Shop by category. Shop by category. Enter your search keyword 99-03 Ford 7.3 7 Powerstroke Diesel WIX Fuel Filter Element with Cap 33818. Brand New. 5.0 out of 5 stars.