When doing an engine overhaul it is common to remove the main and connecting rod bearings and replace them with new ones while the old ones are used for analysis. Some of the causes of bearing failure include; inadequate lubrication, dirt accumulation, overloading, and corrosion, any one of which has to be treated before reassembling the engine, otherwise, it will recur. On the latter, bearings should be taken out of their positions and arranged on a flat surface to align any defects that may be on the crankshaft journal. Contaminants may be introduced to the engine during: assembly, filter, PCV system and; often may be metal chips and abrasives that are used during machining or reconditioning of the engine. Larger Foreign Particles can get lodged in the bearing material surface, and huge particles may cause scoring or gouging of the bearing material surface. That is why proper washing of all components and oil and filter replacement are so important in order to avoid such failures. Where no lubricant is available the reasons may include: high temperatures, overloading, leakage of oil, blocked oil supplies,where bearing metal is removed and the backing gets to overheat. Common traversing behaviors are also very influential in bearing duration; for example, low-speed racing generates high loads that expel the oil while short excursions are eradicative because the heat cannot expunge moisture and gases. Also, when bearings are wrongly positioned, it can lead to oil starvation or there tends to be formation of high spots which lead to failure.