Abstract: The invention relates to a high temperature stability Al—Si—Cu casting alloy with an addition of Sn to improve ageing kinetics and mechanical properties. The alloy is suitable for gravity die casting and comprises 6 to 8 wt. % Si, 2 to 4 wt. % Cu, 0.03 to 0.09 wt. % Sn, 0.05 to 0.1 wt. % Ti, up to 0.2 wt. % Mn, up to 0.2 wt. % Fe, up to 0.03 wt. % Sr, grain refining element in the scale of 1 N kg/ton and unavoidable impurities up to 0.05 wt. %. The alloy may also contain one or more of the following elements: Mg max 0.25 wt. %, Zr max 0.2 wt. % and Hf max 0.5 wt. %. The addition of Sn leads to the finer and denser distribution of O?—Al2Cu precipitates, enhancing the mechanical properties and ageing kinetics of the alloy.