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Characteristic defects of paint and varnish coating (LCP) of car bodies, manufactured according to modern painting technologies, are corrosion damage to the metal roof panel. Defects in the form of corrosion of the roof panel are concentrated on the edge in the place of the regular junction of the windshield. Over time, on the painted surface of the bend of the roof panel at the junction of the windshield there are areas with a breakaway paint material to the metal. LCP above the area of corrosion lesions of the metal has swelling, indicating the spread of sub-film corrosion. A number of defects are accompanied by thread-like, visually similar to the web, swelling of the coating, which should be attributed to thread-like corrosion. The purpose of this study is to analyze the causes of destruction of LCP and the development of measures that prevent the development of corrosion foci, will significantly reduce the costs of manufacturers and car owners for warranty repair and operation. With increasing temperature, the rate of corrosion, as well as many chemical processes, increases, as the rate of diffusion, solubility of corrosion products and other processes increase. In order to study the distribution of heat energy from the standard climate system with a heated internal combustion engine, the mode of directing the air flow to the windshield at maximum performance was selected and measurements of thermal fields were made with the help of a thermal imager. During operation, the temperature of the steel body element (roof panel) is one of the determining factors of the appearance of the studied defects. The development of corrosion in this situation depends on the level of movement of heat flows produced by the climate system, and the thermodynamic resistance of accumulated external deposits in the niche (gap) between the windshield and the edge of the roof panel. Removal of deposits is carried out during washing operations. It is proposed to calculate the frequency of washing operations to prevent the development of corrosion. This study also has practical application in conducting technical examinations by manufacturers and independent organizations.