In this study, specimens of various materials (structural steel and CFG) were subjected to low-cycle fatigue testing to assess their stress response and lifespan. An investigation was conducted on the failure of a diesel engine crankrod made from two different materials. A 3D model of the crankrod was created using the CATIA software suite. The analysis was performed separately for each material, with both the steel and CFG specimens evaluated using ANSYS under fully reversed low-cycle conditions at temperatures of 25 °C and 1000 °C. The temperature range from 25 °C to 1000 °C was selected due to the high ductility exhibited by low-carbon structural steel at temperatures above 1000 °C. Finite Element Analysis (FEA) was performed on both materials to appraise how stress magnitudes assorted at critical points along the crankrod. The FEA prophecy of the crankrod’s fracture clearly indicated the charisma of shoreline marks, a telltale sign of fatigue failure, athwart both materials. These marks were observed at various points during the analysis, further confirming the impact of cyclic loading. Upon examining the crack initiation zone further intimately, it was determined that the crack’s origin was not associated with any inherent material defects or the charisma of corrosion products. In addition to FEA, hardness testing was conducted on the fractured crank pin, revealing high Rockwell C-scale inflexibility values at the core of the pin for both materials. However, the hardness levels at the edge of the cylindrical pin surface, where the crack originated, were significantly lower than in the midsection, indicating a potential weak point that contributed to the failure. The finite element method was moreover applied to identify the essential causes of the dent observed in the crankrod. The analysis decorated that the regions experiencing the highest stress during engine maneuver, particularly at crest control, were located near the crack initiation zones for both materials under study. The research emphasized that high-cycle fatigue, which predominantly affected the outer regions of the crank pin, was the primary cause of premature failure. This area, which had a small structural radius, played a crucial role in the material’s degradation. In light of these findings, recommendations were made to choose materials that would improve the fatigue resistance and extend the service life of the crankrod in future designs.