Anti-wear additives are mostly required to improve lubricant properties and hence tribological performance. Addition of nanoparticles to lubricant oils reduces friction and thus enhances the lubrication characteristics. The mechanism of friction reduction in friction could be justified by more than one method.In this work, copper oxide nano-material was added to the engine lubricant oil Mobil 1 SAE15W-40SF with 0.1% wt. concentration. Two new engines were used and operated for 1000 hours, where nanolubricant was added to one of them and regular lubricant was used in the other. Twelve samples were taken periodically from each engine. ASTM-D6595 spectrometry standard was used in order to measure the wear particles in the taken oil samples. Further investigation was done by doing more tests to some of the oil samples using Laser Net Fines Analyzer.Results showed an improvement in the friction properties through a reduction in wear rates in the case of using nano-additives. Basically a wear reduction is found for aluminum, iron and chromium wear particles by 48%, 11.5% and 42%, respectively. Also, an average reduction in amount of specific wear particle was found by 39%, 36% and 60% for cutting wear, severe sliding wear and fatigue wear, respectively. A relevant decrease in engine temperature is found as well.