NOVELTY - The system (100) has a pair of oil cooling loops (106a, 106b) including a drive unit (102) and a three-way valve (108), where the three-way valve selectively facilitates a thermal coupling of the oil cooling loop to a pair of fuel cell stack cooling loops (114a, 114b) through a liquid to air heat exchanger (24) i.e. radiator. The oil cooling loop is thermally decoupled from the stack cooling loop by diverting flow of oil from the exchanger with the three-way valve. The three-way valve is utilized for coupling and decoupling the stack cooling loop with the exchanger.    USE - Popular fuel cell cooling system for cooling a fuel cell stack and a drive unit for an electric vehicle i.e. fuel cell vehicle.    ADVANTAGE - The cooling loops can be decoupled from the cooling loops by switching the three-way valve to cause the coil to bypass the heat exchanger if the drive unit is colder than coolant temperature at an outlet of the fuel cell stack, thus avoiding a need for the fuel cell stack to reject heat via the cooling loops during a stack warm-up after cold soak. The system allows heat to be transferred to the drive unit when the drive unit is colder than the fuel cell stack and the fuel cell stack rejects additional heat, thus providing high heat capacity. The valve is switched to enable flow of the oil through the drive unit heat exchanger, thus increasing heat rejection of the cooling loop without a need for additional fan power for a certain time interval. The system allows temperature of the fuel cell stack to be avoided to increase a desired set point. The heat capacity of the cooling loops can be used to reduce temperature, thus reducing usage of fans, and hence minimizing noise levels and maximizing efficiency. The system allows airflow to be maximized as the overall pressure drop is minimized by removing the heat exchanger, thus minimizing required package space for the system. The cooling loops maximize transient cooling performance.    DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for a method for cooling a fuel cell stack and a drive unit.    DESCRIPTION OF DRAWING(S) - The drawing shows a circuit diagram of a cooling system for cooling a fuel cell stack and a drive unit for a fuel cell vehicle.    Liquid to air heat exchanger (24)    Popular fuel cell cooling system (100)    Drive unit (102)    Oil cooling loops (106a, 106b)    Three-way valve (108)    Fuel cell stack cooling loops (114a, 114b)