Due to the increasing expansion in the topic of nanotechnology with an emphasis on different nanoparticles like AlO₃, CuO, TiO₂, SiO₂, and CNTs distributed in base oils, this study offers a thorough literature analysis on the impact of regular and hybrid nanofluid addition on the thermal characteristics and heat transfer performance of engine oils. According to the review, adding nanoparticles to engine lubricants greatly increases their thermal conductivity, specific heat capacity, and overall heat transfer rate; gains can range from 10% to 45%, depending on the kind, size, and volume fraction of the particles. Higher concentrations did, however, also result in a rise in density and viscosity, which could have an impact on flow stability and pumping power. Generally speaking, nanoparticle concentrations less than 1.0% by volume yield the best effect. These findings demonstrate how lubricants based on nanofluids can enhance internal combustion engine cooling and energy efficiency while preserving long-term dispersion stability and stable rheological behavior.