The present work aims to address the issue of overcooling at low ambient temperatures in air-cooled IC engines that use fins for heat transfer augmentation. A design modification is proposed to reduce excess cooling at low temperatures in comparison to the heat flux at room temperature. An arc-shaped obstruction placed upstream to the fin, is used to reduce the heat transfer. Two dimensional computational fluid dynamics analysis using ANSYS Fluent is used to study the effect of the obstruction on the heat transfer coefficient of the fin at various velocity conditions for different geometric parameters of the arc. A relationship between the design parameters of the obstruction arc and the heat transfer coefficient is obtained, from which it is observed that the over-cooling can be significantly reduced at certain design parameters of the arc.