Nowadays, many attempts are made to solve tribological issues related to lubricated contacts by the introduction of metallic and non-metallic nano-powders as additives. On the other hand, generated metallic during friction debris can contaminate oil and also can affect its exploitation properties. Therefore, the data collection about tribological behavior of debris or metallic particles-contaminated lubricants has a practical interest. The aim of this work is to investigate the effect of Fe, Cu, and mixture of its meso-particles prepared by colloidal technique on the tribological properties of commercially available motor oil M8V. In this work, the Fe, Cu and Fe-Cu meso-particles were synthesized in inverse micelles directly in motor oil phase by colloidal method by the reduction of FeSO4 by sodium borohydride in the presence of blockcopolymer (ENB 904) or monoalkyl polyethylene glycol ethers based on fatty alcohols (trade mark OS-20) acting as surfactants [1]. Tribological tests were performed using Four-Ball Wear tribotester under standard DIN51350. The effect of Fe, Cu and Fe-Cu meso-particle additives on the tribological properties of lubricating oils is investigated under conditions of 150 N or 300 N loads. The test runs 1 hour. The balls of 12.7 mm diameter were made of 100Cr6 bearing steel (E = 21.98·104 MPa; ν = 0,3). This investigation was carried out in two steps: 1) synthesis of iron, cooper and mixture of iron-copper meso-particles in the motor oil (M8V) and 2) tribological tests on the motor oil with/without Fe, Cu and Fe-Cu particles blended with/without two types of surfactants. The results of this investigation led to conclusions that the addition of Fe, Cu and Fe/Cu particles to the motor oil (M8V) without any surfactants marginal increase in wear scar diameter was observed. As it is shown in Fig.1, different increases of wear scar, as well as torque and reducing of lubricating properties were recorded in the presence of different type of surfactants. The least evolution in wear loss obtained in suspensions with Fe meso-particles, the highest – with Cu and Cu-Fe meso-particles motor oil suspensions. In the studied oil the obtained effect of meso-particles on the tribological characteristics are weaker than that were obtained for other oils such as MOP, SAE-10, and rapeseed oil [1, 2].figureFig. 1. Calculated average diameter of wear scar on the stationary balls obtained under 150N normal load and 1 hour duration, and measured by means of optic microscope.