This paper presents an approach in the context of intergranular corrosion process, its causes, effects and its direct relation with the Engineering, once the responsible professional shall consider the numerous losses that may be caused by this deterioration. The intergranular process of corrosion in stainless steel has been studied. A failure occurred by intergranular corrosion in service in Isolator Exhaust, which is critical to the functioning of the air diesel engine system. A microcrack was generated in the grain boundary region due the precipitation of complex carbides, which was aggravated by the working temperature. Given the working conditions of the isolator exhaust, it is suggested to replace the material AISI 304 with AISI 310, for it contains higher percentage of chromium, inhibiting intergranular corrosion occurrence.