Cooling airflow is driven by a cooling fan situated in the engine compartment of an off road vehicle. To achieve acceptable cooling, fan should supply required cooling airflow at all operating points. Therefore study of airflow through the fan is a must. In this paper fan performance curve is plotted using CFD code to investigate steady state airflow through fan and cooler system over operating range of fan. Radiator is defined as a porous medium and porous coefficients are varied to vary the system restriction of the cooler system. Steady state investigation of airflow through fan and cooler system with increasing system restriction is done. Effect of increasing system restriction on simulated fan curve, fan efficiency and fan power consumption is also studied. Efforts are also made for comparative study between the effect of standard k-ε model and realizable k-ε model on the prediction of fan performance curve. CFD can be used to study the fluid dynamic performance of fan and cooler system even before physical prototypes are available.