Any new Mg-alloys for the power train application in the automotive industry should have better elevated temperature mechanical and corrosion properties than the traditional AZ91 magnesium alloy. The price of AZ-Mg alloy modified with Ca and Sr, which can have adequate properties suitable for its service conditions, is expected to be comparable to that of AZ91 alloy and cheaper than AE42 alloy. The formation of thermally stable intermetallics, which are necessary for the improvement of creep properties, makes it a promising candidate for high temperature applications. This work investigates the mechanical and corrosion properties of AZ-Mg alloy modified with (Ca, Sr) in comparison with those of AZ91; the work included bolt load retention (BLR) and ageing behaviour. The aim is to give a preliminary evaluation of the overall performance of this modified AZ alloy. It is found that this alloy has a superior BLR property compared to AZ91 alloy with a good corrosion resistance.