As a result of its influence on heat transfer between cast part and mould, air gap formation is an important problem for many casting processes. The general explanation for gap formation is that, as a result of stresses and distortions that are created from inhomogeneous cooling, shrinkage of the casting and expansion of the mould occur. In this paper, different thermomechanical approaches are applied to a well defined casting process using three commercial and one inhouse codes and their predictions are compared with experimental findings. The experimental data were obtained from the solidification and subsequent cooling of cylindrical castings of eutectic Al–13%Si and ternary Al–7%Si–0.3%Mg alloys. Based on these findings, the major differences between the predictions of the models and the actual formation of the air gap are discussed.