The recommended oil is a full-synthetic diesel engine oil with a viscosity of 5W-40 that meets API CK-4 (or CJ-4) specifications and is approved for the Cummins 6.7L engine.
In detail, this drivetrain uses modern diesel lubrication designed to work with a diesel particulate filter and high-heat operation. The exact spec will influence protection, performance, and warranty considerations, so always verify with the owner's manual or a dealer if you’re unsure about the allowed oil specification for your build.
Oil grade and specifications
Key considerations when selecting oil include viscosity (5W-40), the API diesel oil classification (CK-4 or CJ-4), and OEM approvals. The following options are commonly used by owners of the 6.7L Cummins engine.
- 5W-40 full-synthetic diesel engine oil that meets API CK-4 (or CJ-4) specifications and is compatible with diesel particulate filters.
- Oils that meet Cummins CES 20081 (for 5W-40) or an equivalent Cummins specification as recommended for the 6.7L engine.
- OEM-approved or Cummins-approved diesel oils when available (look for Mopar or Cummins branding on the label).
Using oils that meet these specifications helps ensure proper lubrication, heat management, and DPF reliability for the 6.7L Cummins engine.
Popular brands and products
Several widely used brands offer 5W-40 diesel oils that meet CK-4/CJ-4 specs. Always check the bottle for current API and Cummins/Mopar approvals before purchase.
- Shell Rotella T6 5W-40 Diesel Engine Oil – commonly listed as API CK-4 capable for modern diesel engines.
- Mobil Delvac 1 ESP 5W-40 Diesel Engine Oil – a frequently recommended CK-4/CJ-4 diesel oil option.
- Amsoil Signature Series Diesel 5W-40 – marketed as CK-4/CJ-4 compatible for heavy-duty diesels.
- Delo 400 XSP 5W-40 – another 5W-40 option that targets CK-4/CJ-4 specifications for diesel engines.
Note: Availability and exact approvals can vary by region and product revision. Always verify current spec labeling and any OEM approvals on the oil container.
Oil change intervals and maintenance notes
Oil change intervals depend on driving conditions. For many 2012 Ram 3500 owners with the 6.7L Cummins, typical recommendations range from about 7,500 to 10,000 miles under normal use; towing, heavy loads, or severe conditions may require more frequent changes. Always follow the maintenance schedule in the owner's manual and adhere to warranty requirements.
Summary
For a 2012 Ram 3500 with the 6.7-liter Cummins diesel, use a full-synthetic 5W-40 diesel engine oil that meets API CK-4 or CJ-4 specifications and is approved for Cummins/Mopar use. Popular choices include Rotella T6 5W-40, Mobil Delvac 1 ESP 5W-40, Amsoil 5W-40, and Delo 400 XSP 5W-40. Confirm current specifications on the oil container and adhere to the vehicle’s maintenance schedule for best results.