Donaldson P550550 P551315 Fuel Filter Water Separator Kit

The Donaldson P550550 and P551315 spin-on fuel filter water separator kit provides primary and secondary filtration for heavy-duty diesel fuel systems. The P550550 water separator features a 78.7 mm outer diameter and 141.7 mm length with 3/4-16 UNF thread. It delivers 95% efficiency at 20 microns per SAE J1488/J1985 and 90% emulsified water separation efficiency. The P551315 fuel filter serves as the high-efficiency final filter stage. Both units utilize cellulose/synthetic blend media with integrated seals and drain valves for water removal. This kit interchanges with Fleetguard FS19594 and FF5324, Baldwin BF1275, Cummins C6003112130, and AirDog WS100/FF100 series. Applications include excavators, wheel loaders, trucks, buses, and industrial equipment powered by Cummins, Perkins, Yuchai, and other diesel engines. Designed for AirDog Air/Fuel separation systems and OEM fuel filter heads requiring spin-on water separator and filter combination.