K805, a nonvolatile aluminum-tin cladding alloy, was developed to provide coolant-side corrosion protection in vacuum-brazed aluminum automobile radiators and heat exchangers. Its performance was evaluated in laboratory glassware corrosion tests of coupon specimens, and a 80 470-km (50 000-mile) simulated service test of vacuum-brazed production automobile radiators. The alloy provided adequate cathodic protection to 3000-series core alloys in corrosive water and depleted glycol automotive coolants. The performance of K805 cladding is compared to that of aluminum-zinc cladding alloys (for example, 7072), the protective properties of which are degraded in vacuum-brazing applications because of the volatility of zinc.