During the last several years, Modine Manufacturing Company has been developing a high reliability, durable heavy-duty (class 7 and 8) truck radiator.This development work has culminated in the Beta-Weld™(1) radiator which was commercially offered to the heavy duty truck markets beginning in June 1982.The objective was to research and develop a heavy-duty truck radiator that possesses substantially improved reliability and durability compared to the “state-of-the-art” soldered tube-to-header joint radiator(2). In addition, it was desired to improve resistance to solder-bloom corrosion which is sometimes a severe field problem.The extensive process and product R&D resulted in the development of a copper/brass, welded tube-to-header joint radiator core, that also incorporates seam-welded tubes. The air-side of the tube-to-header joints are soldered to provide a “dual bond” that reinforces and seals the weld joint.A comprehensive test program was initiated to characterize the structural performance of the Beta-Weld radiator. This paper presents data that compare the structural behavior of conventional-soldered radiators to Beta-Weld™ radiators. Thermal cycle, pressure cycle, and shake-test data are emphasized. In addition, extensive field-test results are also presented.The data show that the Beta-Weld ™ radiator possesses exceptional durability and reliability. The results demonstrate a substantial improvement in resistance to tube- to-header joint failure. Virtually absolute immunity to solder-bloom corrosion has also been documented. Field fleet testing verified the laboratory evaluations.