This fuel filter from Mann Filter removes particulate and water from the fuel supply before it reaches the injection pump. It is installed in the fuel line between the tank and the high-pressure side of the system. A clogged filter restricts fuel flow, causing power loss and erratic engine operation under load. The filter element is constructed to the manufacturer's original specifications, matching the housing seal geometry and bypass-valve cracking pressure of the assembly it replaces. On reinstallation, ensure the housing sealing surfaces are clean and the drain valve is closed before priming the system.