In Conventional internal combustion engine cooling system, the coolant pump is belt-driven by the engine crankshaft. The direct coupling between engine and cooling pump results in an excessive flow of cooling fluid at part-load conditions and waste of energy in running the pump at engine cold start, which affects the engine efficiency and, as a consequence, the global fuel consumption. A study has been conducted on a Maruti 800cc MPFI engine cooling system in order to find a way to reduce common overheating problems at idle conditions and intermediate engine speeds with restricted airflow. The study involves testing of an engine radiator in a wind tunnel (calorimeter) to simulate the actual driving conditions. The coolant flow rate, pressure, and temperature characteristics were monitored at different positions in the cooling system while engine speed and load was varied. Engine performance test were carried out for different radiator ram air speeds. The results show that by adjusting the flow rates according to certain variables, the overall effectiveness of the cooling system can be increased and hence overheating problems can be minimized. A solution is proposed for improving the cooling system by employing an epicyclic gear train to vary the speeds thereby to vary the coolant flow rates in accordance to the coolant temperature.