This study focuses on modeling the reliability and failure rates of two distinct groups of heavy-duty diesel engines (HDDE) with identical capacities, deployed in Excavators. Utilizing Relia-soft Weibull++ software, individual graphs are generated to juxtapose the reliability and failure rate trends of each HDDE group. Various probability distribution models are applied for this analysis. The objective is to determine, within a specific time interval, which group exhibits superior reliability. This assessment is facilitated by comparative analysis of reliability and failure rate plots. By discerning the failure patterns of these engines, a tailored maintenance strategy can be formulated to enhance workshop efficiency, thereby ensuring optimal equipment availability. Time to failure (TTF) data sourced from workshop maintenance logs underpins this investigation.