The objective of this paper is to present a methodology for the cooling system optimization based on experimental and numerical studies. Experimental measurements of fan performance for several truck fans have been carried out in order to determine the representative fan curves. These fan curves have been used to numerically simulate the performance of a truck cooling module consisting of heat exchangers and fan. The cooling module performance optimization has been carried out considering different fans, fan pumping power and fan overdrive ratios. The fan shroud has great influence on the cooling air flow distribution across the exchangers. The test bench has potentials to test a charge air cooler and a radiator at the same time simulating different truck operating conditions. In order to investigate the influence of different shrouds on the performance, experimental measurements and numerical study have been done for several module configurations.