One of the biggest challenges for mobility engineers today is the reduction of fuel consumption while keeping or even improving the automobiles propulsion system performance. A great part of the current powertrain components is developed to work at high engine loads and extreme environmental conditions, among which the engine cooling system, for example. As the overall vehicle efficiency depends directly on the thermal system design, it is important to make a careful investigation of the external ambient to develop this system on the best possible way, seeking to minimize the negative impacts at normal driving situations, which represents the most of the vehicle's life cycle. In this regard, the present paper reports a numerical study about the impacts of different cooling system hardware configurations on the fuel consumption of a turbocharged flex-fuel engine. By means of a ID CFD commercial software, the effects of radiator size and fan power on the fuel consumption of a vehicle under the Federal Test Procedure (FTP-75) and Highway Fuel Economy Test (HWFET) cycle were analyzed. The combinations between radiator and fan were chosen for the system with the same cooling capacity, according to the required performance on high loads and extreme environments conditions, characteristics of the Davis Dam tests. At the FTP-75 and HWFET cycle, the results showed that radiator size was the most influential parameter on fuel consumption, due to its effects on aerodynamic cooling drag. For each 3% increase in the vehicular aerodynamic drag coefficient, there was a 1% increase in fuel consumption. For lower energy consumption, it was preferable to increase the electric fan power rather than the radiator size, and this decision may result in lower costs, improved packaging in the engine compartment and total vehicle weight reduction, but, on another hand, may worsen the electrical balance and increase battery and alternator. A trade-off between these performance parameters should be made for a final design decision.