Most automotive piston engines employ a front-mounted, belt-driven coolant circulation pump. The pump shaft is normally supported by a double row rolling-element radial contact bearing.The engineering analysis for an improved method of water pump bearing service load and life prediction is described here. This general analysis considers most of the design variations which are found among engines, water pumps, and bearings in current use.A rather thorough accounting has been made here of the various sources of bearing loading occurring in this application. Bearing life is determined according to the recently revised A.F.B.M.A. standards.