Fuel filtration is of prime importance for diesel engines. The filters must be high efficiency units specifically designed for diesel service. Maintenance must be followed regularly to maintain a smooth and reliable running system. Fuel filters for diesel service cannot be treated with the complacency given filters in gasoline service. Water should be removed at a point before the injectors.
Some fuel filters combine water removal features and filtration features in the same package.
Diesel fuel systems from process, to storage tanks, to engines, traditionally contain much more water than gasoline systems. Water is a definite problem in diesel fuels and it must be coped with. Low temperatures tend to precipitate wax in diesel fuels. In order to get the fuel to flow through filters correctly, it is generally heated in the fuel system of the engine. Certain lube oils are specifically designed for diesel service.