When an engine is overhauled, it is advisable to fit new main and connecting rod bearings, while retaining the old ones for analysis, to deduce the state of the engine. The main root causes of bearing failure include, inadequate lubrication, dirt contamination, overloading of the engine and corrosion and all these root causes must be remedial before any reassembly is made to avoid repetition. When inspecting bearings they are withdrawn from their appropriate place and placed on a flat surface with a view of matching the defects with the crankshaft journal. Contaminants are brought into the engine during assembly or even through the filters, as well as during the machining processes, and our experiences show that such contaminants get lodged on the bearing surfaces and thereby create scores or gouges on the bearing material. To avoid such a failure, it is essential to clean every part carefully always change the oil and the filter frequently. This arises from one of the following causes: heat, overloading, leaking of oil and blocked passages and as a result can cause severe damage where the bearing material is entirely wiped off. Again, habits in driving are antonymous with bearing durability; for instance, in luging the engine or in short trips, there can be overload and corrosion respectively. Further, substandard mounting of bearings also provokes a lack of supplies of oil and high areas associated with failure.