Abstract: “One of the methods commonly employed for enhancing the lubricity of oil is the addition of solid lubricant nanoparticles, possessing lamella structure, in it. Even though higher concentration of nanoparticles will lead to better reduction in the friction and wear, stability of nanoparticle added oil has to be ensured to prevent the sedimentation of the nanoparticles, especially at higher temperatures. Present work mainly focuses on the stability of MoS2 nanoparticles in engine oil. MoS2 nanoparticles were synthesized by wet chemical synthesis method and were mixed in the engine oil (15W40), with the help of a standard ultrasonic shaker. Sodium dodecyl sulfate was used as surfactant to improve the stability of nanoparticle added oil. Optimum concentration of Sodium dodecyl sulfate in engine oil was determined by bubble pressure method. Stabilization study at different temperatures was done by using DLS. The properties of nanoparticle added oil such as viscosity, pour point, flash and fi”

Keywords: MoS2 nanoparticles, Stability, Viscosity.