The classical mechanism of crevice corrosion in stainless steels is well known from literature. This phenomenon becomes more critical in some industrial applications where corrosive mediums in combination with alternating heating and cooling cycles are involved. No systematic studies have been performed so far to study the interaction of crevice corrosion in combination with sensitization and heat cycling of stainless steels. This project relates to issue of crevice corrosion in automotive exhaust system, a complex assembly of various components performing important tasks in harsh environments. The aim of this work is to study the role of temperature cycles on acceleration of crevice corrosion with different crevice widths. Furthermore, this research seeks to contribute to the understanding of the corrosion science due to salts and acidic condensates separately. The grades used in this study are ferritic and austenitic stainless steels. Besides the properties of the materials, the design of the muffler itself has a big influence on its corrosion resistance. This was also observed from the results of the field studies. To predict the life time of a complete system under real conditions is always a difficult task and sometimes also uncertain. A new testing method was developed during this research in which simulation of material and design can be performed simultaneously.