Sinister Diesel 07.5-12 Dodge 6.7L Cummins Coolant Filtration System w/ Wix FilterEven on freshly rebuilt, or brand new engines, the coolant is usually contaminated with microscopic particles including casting sand leftover from the manufacturing process, metal shavings, rust, and mineral deposits that can diminish the cooling system's ability to absorb heat. If these particles are left inside the engine, they can actually cause premature wear to the bearings inside your water pump and cause expensive damage to the small passages