Abstract: The present invention provides a system for the automatic removal of contaminants such as water from the fuel supply of an internal combustion engine of the type including an auxiliary fuel tank. The system is automatically controlled and responsive to sensed contaminant levels in a contaminant removal mechanism and employs an existing fuel transfer pump to direct fuel around the auxiliary fuel tank through the contaminant removal mechanism. The pump additionally operates to provide a continuous supply of fuel to the engine to keep it operating while simultaneously permitting the discharge of contaminants from the contaiminant removal mechanism when a predetermined maximum contaminant level has been reached. This system is especially effective in removing water from the fuel system of a diesel engine powered vehicle such as a tank wherein the engine and auxiliary fuel tank are components of a power pack that is removable from the tank.