The preparation of silica-coated magnetite nanoparticles as a lubricant additive has been successfully carried out. The material was prepared using a combination of coprecipitation and ultrasonic methods. In this study, SEM characterization was also performed to support morphological analysis, XRD was performed to determine crystalline properties, and FTIR analysis was performed to help identify functional groups. Based on these characterizations, the silica was successfully coated with magnetite. Then, AAS testing, Viscosity, and lubricant tests were conducted to assess the impact of adding silica-coated magnetite to the lubricant. The stability of lubricants using magnetite, both without and with the addition of TEOS, at a viscosity of 100°C, is 8.65 mm²/s and 8.96 mm²/s, respectively, for lubricants and nano-lubricants. The total base number showed the exact value of 0.55 in both the lubricant and nano-lubricantnano-lubricant.