Adding of nanomaterial to car radiator fluid for 4-stroke gasoline engine was investigated experimentally at different Nanofluid concentrations with different flow rates for variable car speeds and number of passengers. The fluid temperature and exhaust gases emissions have been carried out. Results demonstrate that the increasing of Nanofluid concentration and high fluid circulation rates can improve the heat transfer of the engine radiator response; also using Nanofluids reduces the CO and NOx emissions of the engine exhaust gasses, while the CO2 ratio has been increased.