Automobile engine reliability, maintainability and oil maintenance

This paper provides an investigation of the effectiveness of the oil change, one of the most basic procedures for automobile engine preventive maintenance. The analysis in this paper is based on a review of oil, engine, and bearing technologies and on a survey of vehicle operators. The oil development, specification and approval process is also discussed. The results indicate engine reliability is significantly dependent on the period between oil changes. Surprisingly, the survey data shows that oil changes, when too frequent, can reduce the expected life of an automobile engine. The unexpected outcome is supported by lubrication technology literature. Changing engine oil at the proper mileage can improve engine reliability and has the potential to reduce nationwide waste and recycled oil by 325 million gallons annually. Despite more demanding conditions, engine reliability has also improved. Many automobile operators change engine oil more frequently than required by the manufacturer. All automobile manufacturer's provide oil change mileage recommendations which are based on the climate and the type of driving. A query in the operator's manuals is used to determine this mileage and most manufacturers require oil changes at about 7500 miles for "normal service" or 3000 miles for "severe service". This paper concludes that automobile engine reliability will be improved by using these recommended oil drain intervals with potential results of a significant nationwide reduction in waste and recycled oil.