Automobile heat exchangers with excellent performance have become increasingly important in recent years owing to the growing demand for saving energy. The tubes are usually produced by rolling flat strips of AA3xxx aluminium alloys cladded with AA4xxx alloys on either or both sides. Preheat parameters are tightly controlled to ensure the correct size and distribution of Mn-bearing dispersoids that form when Mn precipitates out of a solid solution. If the alloy is soaked for a longer time or higher temperatures before hot rolling, it results in more manganese (Mn) precipitating out of the solid solution resulting in larger Mn dispersoids leading to the final product having low mechanical properties. Therefore, it is crucial to optimize the different manufacturing steps, such as homogenization, soaking time, and brazing to achieve a high-quality product. In this study, the role of soaking time on the mechanical (yield and tensile strength) properties of tube stock for automotive brazing sheets used for heat exchangers was investigated. Aluminium plate was preheated at 505 °C for three different holding times of 20, 35, and 40 h with the AA4045 as a clad alloy and the AA3003mod as a core alloy. The alloys were roll-bonded to have a final thickness of 300 μm. The tensile and yield strength of samples preheated at 505 °C for longer residence times of 40 h, cold rolled and annealed was found to be on the lower end of the 9031-H24 specification.