In the present work, experimental and numerical investigations have been performed to determine the performance of an automotive radiator using louvered–fin geometry with reference to flat-fin geometry. Four radiators specimens were designed and manufactured, three specimens with different louvered fin per inch and the other with flat fin. The experimental work was carried out on a four cylinders petrol engine (Seat-124A).The effects of engine speed, number of fins per inch (FPI), Reynolds number and radiator boundary conditions on the radiator performance were investigated at a certain louvered angle of 25º. The specific fuel consumption was also investigated experimentally. Numerical CFD investigation using finite volume discretization method was also conducted to predict the radiator performance extensively. The momentum and energy equations were solved by the second order up wind scheme. The air flow and heat transfer through the louvered fin passage were treated using the k- RNG turbulence model. For the validation of the numerical model, the numerical results were compared with corresponding experimental data. It was noticed that the level of the turbulence increases through the transition region of the louvered flowpassage which will lead to a disturbance of the boundary layer thickness and hence, the increase in the heat transfer coefficient was achieved.. The results indicated that an improvement of about 23% in the Nusselt number and a decrease of about 19% in the specific fuel consumption at full load could be achieved due to using louvered-fin geometry compared to flat-fin geometry at the same operating conditions.