About 15W-40 Heavy-Duty Diesel and Marine Oil
15W-40 Heavy-Duty Diesel and Marine Oil for compatible diesel engines. Compare the current AMSOIL application information with your equipment’s service documentation before planning the job. Keep the product code AMEQT-EA handy when reviewing package options or asking Jeff a question.
Before you choose
Confirm the viscosity, required diesel-oil performance category, and equipment manufacturer’s specification. Review compatibility with the engine’s emissions equipment.
Does every diesel engine use the same oil?
No. Model year, engine design, emissions equipment, and duty cycle can change the required oil. Match the current product data to your engine’s documentation.
Product information reviewed September 7, 2026. Read AMSOIL’s current details.
