The 2018 Ram 2500 with the 6.7-liter Cummins turbodiesel requires a full-synthetic diesel engine oil that meets API CK-4 (or CJ-4) specifications and is typically a 5W-40 viscosity. Mopar-approved 5W-40 or an equivalent CK-4/CJ-4 diesel oil is appropriate.
In more detail, the Ram/Cummins combination demands a high-quality diesel oil that supports modern emission controls and provides reliable cold-start protection. This article outlines the recommended viscosity, API spec, typical oil capacity, and maintenance intervals to help you choose the right oil and plan service intervals. Always consult the owner's manual or a dealer for the exact requirements for your vehicle.
Oil specifications for the 6.7 Cummins
Before listing the key requirements, here are the main points to verify on the oil you buy:
- Viscosity: SAE 5W-40
- API service category: CK-4 or CJ-4 (diesel engines with particulate filters)
- Oil type: Full synthetic diesel engine oil
- Approvals: Mopar/Chrysler-approved or equivalent meeting CK-4/CJ-4
- Note: Dexos is for gasoline engines; not required for diesel engines
Conclusion: For a 2018 Ram 2500 6.7 Cummins, choose a 5W-40 full-synthetic diesel oil that meets CK-4 or CJ-4 and is approved for diesel engines.
Oil capacity and maintenance intervals
Key maintenance figures to plan your service around:
- Oil capacity: Approximately 12 quarts (11.4 liters) with a replacement filter
- OCI (normal driving): About 15,000 miles (24,000 km) with synthetic oil; shorter under severe conditions (7,500–10,000 miles)
- Oil filter: Replace at every oil change
- Drain-and-fill procedure: Drain old oil completely, replace the filter, and fill to the specified capacity with the recommended oil
Conclusion: Following these guidelines helps ensure optimal lubrication, emissions-system protection, and engine longevity. Always verify exact OCI and capacity in your owner's manual for your VIN and configuration.
Practical tips for selecting and maintaining oil
Helpful considerations when shopping for oil and planning maintenance:
- Use a high-quality full-synthetic diesel oil that meets API CK-4 or CJ-4
- Ensure the oil is suitable for diesel engines with particulate filters and good cold-start performance
- Avoid oils labeled only for gasoline engines or that do not meet CK-4/CJ-4
- Prefer OEM-approved brands (e.g., Mopar) or reputable third-party oils with CK-4/CJ-4 approval
Bottom line: For a 2018 Ram 2500 6.7 Cummins, select a 5W-40 full-synthetic diesel oil that meets CK-4 or CJ-4, and plan to use roughly 12 quarts with an oil-change interval around 15,000 miles under normal driving.
Summary
The 2018 Ram 2500 6.7 Cummins takes a full-synthetic diesel oil that meets API CK-4 (or CJ-4) specifications, typically in 5W-40 viscosity. The engine capacity is about 12 quarts with a filter, and a typical oil-change interval under normal conditions is around 15,000 miles (more frequent with severe service). Always confirm exact requirements in the owner's manual or with a dealer.