The demand for the materials required for manufacturing automotive vehicles is increasing due to the increased production of vehicles in the automotive industry. To satisfy these demands, researchers are focusing to reduce the overall weight of the vehicle by finding alternate solutions to maintain the same efficiency. In this experimental and statistical investigation, Silicon carbide (SiC) nanofluids of different sizes are analyzed to enhance the heat transfer properties of an automotive radiator so that the size of the radiator can be reduced. Results showed that low sized nanoparticles of 24 nm have higher heat transfer properties than large-sized nanoparticles of 110 nm. The settling velocity of 2.075 is obtained for 24 nm-SiC at a 3% volume concentration by using Response Surface Methodology. The higher Brownian velocity of 9.453 was obtained by using 24 nm-SiC at a 3% volume concentration proving that low sized nanopartides have a high impact than large-sized nanoparticles. It is concluded that utilizing lower sized nanoparticles with the base fluid will enhance heat transfer and can reduce the size of radiators compared with the conventional coolants. (C) 2020 Elsevier B.V. All rights reserved.