Volume of structural castings produced by high pressure to 2020. Alloys’ and tempers’ mechanical properties such as yield strength and elongation play an important role in automotive part design. However, part failure is often linked to fatigue crack growth. Fatigue strength and fatigue life are therefore critical aspects in the design of castings. Fatigue life can be affected by various parameters such as chemistry, temper and defects. In this paper, the low-cycle and high-cycle fatigue life of three Aural™ alloys were evaluated to study the impact of the silicon and magnesium content, as well as the impact of temper and defects. Strain-controlled fatigue testing was used to obtain a complete strain-cycle curve in both the low and high-cycle regimes. Fractured surfaces were analyzed to determine the crack initiation site. The samples’ microstructure and crack propagation route were analyzed to determine the key microstructural aspects to obtain good fatigue life.