The development of newer and enhanced diesel fuel injection and the introduction of different fuel properties with newer additives associated with other mechanisms to assure environmental protection introduces significant challenges in the maintenance of vehicles. The objective of this research work was to analyze the vehicle maintenance strategy that would allow for adequate engine reliability and more efficient resource management, taking into consideration the vehicle activity, the fuel, and the lubricant oil degradation. To assess whether the fuel may have some influence on engine degradation by lubricant contamination, this study was conducted, based on a set of heavy-duty vehicles, in real operating conditions, considering periodic analyses made to the lubricating oil of these vehicles. The present work considers truck fleets monitorization, a methodology definition to get oil samples, fuel samples, and fuel filters. This work involves the time interval settings for oil sampling and the implementation of several techniques, which not only allow the prediction of mechanical failures and wear but could also be used to adjust oil change intervals. The adequate condition of the lubricant and engine to vehicle type of use was analyzed considering the data obtained in this study. The predictive maintenance technique employed granted improved sustainability, reducing costs and residues and improving global engine efficiency.