This fuel filter with an integrated water separator removes particulate and liquid water from the fuel stream before it reaches the high-pressure injection system. It mounts in the engine bay on the supply side of the fuel loop, downstream of the tank and upstream of the lift pump. The water separator element collects free water at the bottom of the housing, which can be drained during routine service. A clogged filter element restricts fuel flow, causing hard starting, power loss, and potential cavitation damage to the injection pump. The manufacturer machines the sealing surfaces to match the housing bore, ensuring the separator bowl seats correctly and the drain valve operates without leaks. Replace the sealing O-ring on reinstallation and tighten the housing to the specified torque.