This fuel filter removes particulate and water from the fuel supply before the fuel reaches the injection pump. It is installed in the fuel line between the tank and the high-pressure pump, where it protects the injectors and pump internals from abrasive contamination. A restricted filter causes a pressure drop that leads to hard starting, reduced power, and uneven engine operation. The filter uses a spin-on canister with a threaded mounting base; the thread pitch and seal diameter match the original housing so the filter seats without leaks. On installation, lubricate the seal with clean fuel and tighten the canister by hand until the seal contacts the housing, then advance an additional three-quarters turn.