Delve into the exceptional performance of AMSOIL 4X Synthetic Heavy-Duty Diesel Oil, specifically designed to meet the rigorous demands of your diesel engine. With its 15W-40 viscosity rating, it provides the ideal balance of protection and efficiency for both heavy-duty and everyday driving conditions. The synthetic base ensures a high-quality lubricant that resists degradation, while the unique formulation enhances engine longevity and power. Trust in the AMSOIL brand to deliver a product that surpasses conventional diesel oil, ensuring your engine runs smoothly and reliably. Part Number: 15W-40.