The paper presents the results of laboratory studies of a number of additives introduced during operation to motor oil of internal combustion engines. It also evaluates their impact on tribological characteristics of friction pairs. It was found that all studied additives have a positive effect on the running-in quality. Reduced wear of friction pairs, reduced surface roughness compared to base motor oil is determined. The best indicators were recorded with the FENOM additive. The decrease in wear was 46% and roughness – 23.5% compared to the base oil
