The paper aims to determine the failure cause of an internal combustion engine, in a particular case for a medium displacement diesel engine. The assumed analysis for achieving this objective is complex and involves a multidisciplinary and gradually approach of the problem, as well as the development of an appropriate methodology to ensure the accuracy of the outcome. In principle, the cause of the engine breakdown is related to its mobile equipment. Based on this assumption, the authors identified all the affected moving parts organs and defined the damage they recorded. The present paper is a real „good practice support” in approaching the causes of fatal destruction of engines, based on a case study.