The crankshaft is one of the main components of the combustion engine used for continuous rotation. Therefore, this research aims to analyze the crankshaft failure of a jeep with a four-cylinder diesel engine used to transport 4 tons of logs on rugged terrain and uneven roads for 12 months. This research was carried out using the Scanning Electron Microscope (SEM), microstructure, hardness, chemical composition, and stress analysis testing methods. The chemical composition and microstructure test results showed that the crankshaft was made of AISI 3150 material with a pearlite phase. From the results of the visual observation on the fracture surface, the characteristics of failure due to fatigue are indicated by a beach mark pattern on the fracture surface. SEM test shows a crack initiation at the edge of the balancer due to the dynamic loads experienced by the crankshaft, which causes propagation from the initial beach marks pattern to the final fracture.