This fuel filter element removes particulate contamination from the fuel supply before it reaches the injection system. It is installed in the fuel line between the tank and the high-pressure pump. A clogged filter restricts fuel flow, causing power loss and rough running, and can allow debris to bypass the element if the internal relief valve opens. The manufacturer specifies the filter housing seal should be replaced when this element is changed, and the housing cap must be torqued to specification on reinstallation.