Today's worries and doubts related to the use of mineral oils increased because of the worldwide interest in environmental issues. This issue has increased the use of vegetable oils as an alternative lubricating oil candidate, environment-friendly lubricant and their additives. In this study, rapeseed oil (RSO) in different concentrations, 1, 2, 3, 5, 10, 20, 30, 40, 50 (by volume percent), was added to base oil to obtain a lubricating oil candidate. Turkish originated RSO was studied as an additive candidate in this paper. The study of the effect of additives in mineral oils was carried out using a specially designed experimental system to compare lubricating oil candidates and high temperatures using engine journal bearings under statically loaded.