Corrosion of free machining Al alloys that contain Sn and Bi was investigated at 391–415K in 2-(2-(2-methoxyethoxy)ethoxy)ethanol (MEEE) and 2-(2-(2-butoxyethoxy)ethoxy)ethanol (BEEE) with/without SnCl 2 , Sn(OC 2 H 5 ) 4 , FeCl 3 , and CuCl 2 . The Al–Sn–Bi alloy displayed severe pitting corrosion in MEEE similar to the Al–Sn alloy in BEEE at 415K, and Sn and Sn/Bi were enriched on the surface of pits. Immersion tests of pure Al in MEEE containing Sn/Cu-salts at 415K also showed severe corrosion and the deposition of metallic Sn and Cu on the surface. The corrosion mechanisms are discussed in terms of the electro-catalytic activity of the Sn enriched on the surface.