Demands on longer life time, lower weight, mixing of different materials and last but not least changed corrosion conditions due to pollution and climate conditions have made the corrosion behaviour both externally and internally of automotive heat exchangers more important in recent years.This paper presents our experiences from both field and laboratory tests of copper/brass and aluminium radiators together with some literature results. The main part is dealing with external corrosion. Comments are given on the influence of material properties, production methods and ways of protection. In the case of copper/brass results, from trials and use of an improved corrosion protection with a special type of lacquer are presented.In conclusion, it is stated that the competing materials mentioned, show different characters from a corrosion point of view. These differences are, however, not considered significant enough to be decisive for the choice between copper and aluminium materials for automotive heat exchanger.