Mann Filter - WK8100 - Fuel Filter With Water Separator

This fuel filter with an integrated water separator removes solid contaminants and separates free water from the fuel before it reaches the injection system. It is installed in the fuel line between the tank and the high-pressure pump. The water separator collects heavier water droplets at the bottom of the canister, where they can be drained during routine service. A clogged filter element restricts fuel flow, causing a pressure drop that leads to hard starting, loss of power, or erratic engine operation. The manufacturer specifies the filter's sealing geometry and bypass-valve cracking pressure to match the original housing, ensuring the filter seals correctly and the bypass valve opens only when the element is fully loaded. On replacement, drain the water collection bowl and verify the seal ring is seated in the housing groove before tightening the canister.