The numerical simulation of an electric machine (E-machine) used for hybrid electric vehicle, electric vehicle, and plug-in electric vehicle is carried out to explore the impact of distinct kinds of coolants such as water and distinct nanofluids on the bracket housing cooling performance. Nanofluids are stable nanofiber and fluid particle suspensions. Recent research shows that these nanofluids have enhanced thermal conductivity and convection coefficients, are superior to pure fluid. The aim is to understand the heat transfer enhancement brought by different nanofluids. The present study suggests that the use of Ga-In-Sn (Gallium, Indium, and tin) as the coolant leads to higher efficiency of heat transfer compared to other nanofluids agents and base fluid. Results indicate increased heat transfer in the cooling of the electrical machine as shown by a significant reduction of ∼ 30% in the operating temperature when using nanofluids compared to pure fluid implementation. With superior thermal characteristics and countless advantages, nanofluids are promising to meet the cooling requirements of the machine by a reduction in thermal resistance and maximum temperature. © Published under licence by IOP Publishing Ltd.