Automobiles and motorbikes need cooling circuits to remove heat from their engines. Heat is rejected to the coolant that transfers it to the surrounding environment in the radiator. In order to maximize the heat transfer at the radiator, fans are employed. These fans are typically of the axial flow type, given the requirements of high flow rate with relatively low pressure drops. The requirements of high efficiency and low noise of axial flow fans are pushing manufacturers and researchers to look into the operation of these machines in the effort of minimizing losses and noise source. For this reason, ad-hoc test benches are developed for the experimental analysis. Over the last decade, numerical simulations with CFD software have become an industrial standard for complementing and getting insight into the experimental evidence and propose solutions. Among the possible CFD suite available, OpenFOAM is gaining an increase share of the market due to its opensource nature and the great accuracy and reliability of the results. In this work the authors presents the CFD investigation of an axial flow fan with OpenFOAM. The results are compared with experimental data obtained in twoa test benches: one ad hoc developed for acoustic and flow field analyses and one build in compliance with ANSI/AMCA Standards for performance determination. The capability of the software of correctly replicating the fan performance and flow filed even in this complex set-up (due to the loose constraints of the fluid flow) is shown both with steady and transient simulations.