The 2026 Ram 3500 uses different oils depending on its engine: the diesel-equipped models with the 6.7L Cummins turbodiesel typically require a high-quality diesel oil such as 15W-40 meeting Cummins CES specifications, while the gasoline-powered models with the 6.4L Hemi generally take a 0W-20 full-synthetic that meets Mopar/Chrysler specifications. Always verify the exact spec on the under-hood oil cap or in the owner's manual for your exact build.
This article explains the oil requirements for the two available engines in the 2026 Ram 3500, including recommended viscosities, required certifications, and practical maintenance notes. It covers the diesel and gasoline options, then addresses capacity, selection tips, and how to confirm the correct oil for your truck.
Engine options and oil recommendations
Diesel: 6.7L Cummins Turbo Diesel
The diesel version of the 2026 Ram 3500 demands a diesel engine oil that meets Cummins specifications and common diesel API standards. The typical recommendations emphasize durable, high-temperature resistance and compatibility with turbocharged diesels. The recommended viscosity is generally 15W-40 for most ambient conditions, with 5W-40 synthetic acceptable in colder climates. Oil that meets Cummins CES specifications (such as CES 20079/20081) and API CK-4 is usually specified by Ram for this engine.
Key oil specs for the diesel engine:
- Viscosity: 15W-40 (default); 5W-40 synthetic for cold climates
- Certifications: Cummins CES 20079/20081; API CK-4
- Capacity: Approximately 13–15 quarts with filter
Concluding: Always confirm the exact CES number and CK-4 rating listed on your vehicle’s owner’s manual or under-hood sticker, as requirements can shift with model-year updates or emission packages.
Gasoline: 6.4L Hemi
The gasoline-powered Ram 3500 uses a different oil spec from the diesel. For the 6.4L Hemi, Ram commonly specifies a full-synthetic 0W-20 that meets Mopar Chrysler specifications (often referenced as MS-6395 in official documents) and API SN/ILSAC GF-6 ratings. This oil is chosen to provide good cold-start performance and fuel efficiency while protecting a high-compression gasoline V8.
Key oil specs for the gasoline engine:
- Viscosity: 0W-20 (full synthetic) as standard recommendation
- Certifications: Mopar MS-6395; API SN/ILSAC GF-6 (or newer)
- Capacity: Approximately 6–7 quarts with filter
Concluding: Always cross-check the exact MS-6395 revision and the current API/ILSAC standard in your manual, as specifications can be updated for new emissions technology or regional requirements.
Oil capacity, maintenance tips, and how to choose
Understanding capacity, change intervals, and climate considerations helps ensure you select the right oil and service cadence for your Ram 3500. The numbers below are approximate and vary by engine and configuration; always rely on the official manual for your exact build.
- Diesel oil capacity (6.7L Cummins): roughly 13–15 quarts with filter; use the recommended CK-4/Ces spec oils
- Gasoline oil capacity (6.4L Hemi): roughly 6–7 quarts with filter; use 0W-20 full synthetic per Mopar MS-6395
- Change intervals: typically longer intervals with full-synthetic oils (often around 10,000–15,000 miles for normal service, but severe service or extreme conditions may require more frequent changes)
Concluding: If you drive in extreme temperatures, dustier conditions, or frequent heavy towing, follow the shorter end of the recommended range and perform oil changes sooner. Always replace the oil filter with every drain to help maximize oil life and engine protection.
How to verify the correct oil for your 2026 Ram 3500
To ensure you have the exact specification for your vehicle, perform these checks:
- Inspect the under-hood oil cap, which often lists the viscosity and a reference specification (e.g., 0W-20 Mopar MS-6395 or 15W-40 CK-4).
- Consult the owner’s manual or the Ram service portal for your specific VIN; some updates alter the recommended oil standards by emission package or regional requirements.
- When in doubt, ask a Ram dealership service advisor or a trusted mechanic who can read the exact specification printed on your vehicle's data plate.
Concluding: Correct oil choice is engine-specific and year-specific. If you have a 2026 Ram 3500, double-check the precise spec for your trim and engine to avoid using an oil that doesn’t meet Cummins CES or Mopar MS-6395 requirements.
Summary
The 2026 Ram 3500 can be equipped with either a 6.7L Cummins turbodiesel or a 6.4L Hemi gasoline engine, and each has its own oil requirements. Diesel models typically use 15W-40 diesel oil meeting Cummins CES and API CK-4, with 5W-40 synthetic as a cold-climate alternative. Gasoline models typically use 0W-20 full synthetic meeting Mopar MS-6395. Confirm the exact spec from your owner’s manual or the under-hood sticker, and adhere to the recommended oil change intervals based on your driving conditions. Proper oil selection protects your investment and keeps the Ram 3500 performing at its best.”