H ot climate change and the weight of vehicle travel for now is very large, impacting on high engine temperature of the vehicle. Because vehicle engines produces heat that results in their own combustion chamber, and are also exposed to heat from the surrounding environment. Therefore a redesign of the radiator is very important so that the engine temperature is at its optimal temperature. By enlarging the surface area of the tube and its fins, the radiator can release larger radiator water heat too. The 2015 Honda Brio Satya S M / T radiator has a total surface area of 6.68m2. Then the redesign of the designed radiator is enlarged to its total surface area of 7.55m2. This study analyzes the value of the reference radiator heat transfer rate using from the experimental results using a flow meter and thermocouple temperature reader as well as analyzing the value of the design radiator heat transfer rate with data from the Computational Fluid Dynamic (CFD) simulation software and analytical calculations. Performance of the designed radiator shows that it can reduce the radiator water temperature by 9°C, larger compared to the reference radiator which can only reduce the water temperature by 7°C. Also the rate of heat transfer convection on the design tube and radiator fins is larger than the reference radiator.