Cross flow heat exchangers are very common in automotive vehicle thermal management systems. The most important and standard fitment of any vehicle is the radiator, a cross flow heat exchanger for engine cooling systems. As a vehicle manufacturer, selection of a cooling system based on the requirements is very critical especially when the radiators are sourced from multiple sources and of different configurations. So, these different types of radiator have to be compared on the same level for effective selection of heat exchangers. This demands the common methodology to be created to understand the heat exchanger performance with different geometrical input from different sources.In this study, an empirical cum analytical based methodology has been developed for generating the performance characteristics of the louvered fin heat exchanger using the thermal resistance and Number of Transfer Units (NTU) method. This methodology was validated with the experimental data for an engine cooling radiator. Experimental approach involved selecting a radiator and subjecting it to a wind tunnel test for different air and coolant flow. Using these component characteristics, radiators of different make and specifications can be effectively and consistently compared. This methodology will reduce the number of vehicle cooling trails performed for replacing/selecting the radiators thereby reducing the product development lifecycle cost, and time.