This fuel filter from Mann Filter removes particulates and water from the fuel supply before the fuel reaches the injection system. It mounts in the fuel line between the tank and the high-pressure pump. A clogged filter restricts fuel flow, causing power loss and rough running; a fully blocked element can starve the pump and lead to injector damage. The filter uses a spin-on design with a sealing gasket that must be replaced with each change. Tighten the filter by hand until the gasket contacts the mounting head, then give an additional three-quarter turn.