The 6.7L Cummins diesel engine is renowned for its reliability and powerful performance, especially in Ram trucks. If you own a Ram truck equipped with this engine, understanding its motor oil requirements will ensure optimal engine life and performance. This guide explains the exact 6.7 Cummins oil capacity , the optimal oil type, and how to maintain it to maximize engine life.
How Much Oil Does a 6.7 Cummins Take?
For the 6.7L Cummins, oil capacity will vary slightly depending on whether the oil filter is changed. Here is a breakdown by year of oil capacity for the 6.7L Cummins trucks with and without oil filter changes:
| Year Range | With Filter | Without Filter |
|---|---|---|
| 2007.5–2018 | 12 quarts (11.4 L) | ~11 quarts (10.4 L) |
| 2019–Present | 10 quarts (9.5 L) | ~9–9.5 quarts (8.5–9 L) |
Why the difference matters: The oil filter holds and circulates a portion of the engine oil.
Best Engine Oil Type for 6.7L Cummins Engines
The ideal motor oil for a 6.7L Cummins engine depends on the model year and operating environment. Regardless of the year, synthetic oil is recommended over conventional mineral oil. Synthetic motor oil reduces friction and wear and, while more expensive, lasts longer.
Oil Specifications
To ensure smooth engine operation and protect the aftertreatment system (DPF/SCR), always use oil that meets API CK-4 or CJ-4 standards:
- CJ-4 : Suitable for older models; can be used as an alternative when CK-4 is unavailable.
- CK-4 (Current Standard): Meets 2017 and later emission standards and is backward compatible with older engines.
Viscosity Recommendations
The oil viscosity grade should be determined based on the model year and ambient temperature:
2007.5–2018 Model Years
- Above 0°F (-18°C) : Recommended 15W-40 full synthetic oil.
- All temperatures (including below 0°F) : Recommended 5W-40 full synthetic oil.
2019 and Later Model Years
- Above 0°F : Recommended 10W-30 full synthetic oil.
- 0°F or below : Recommended 5W-40 full synthetic oil.
Common Application Scenarios
- 10W-30 CK-4 : Factory recommendation, suitable for most climates, may improve fuel economy.
- 15W-40 CK-4 : Suitable for warmer climates or frequent heavy towing.
- 5W-40 CK-4 : The most comprehensive option, suitable for cold climates, wide temperature ranges, and year-round heavy use.
Cummins Engine Oil Change Recommendations
| Usage / Model Year | Oil Change Interval |
|---|---|
| Normal driving | Change oil every 8,000-10,000 miles (12,800-16,000 km) or annually |
| Heavy-duty towing/transportation | Change oil every 5,000-7,000 miles |
| 2007.5-2012 model years | Change oil every 7,500 miles or every 6 months (whichever comes first) |
| 2013 and later model years | Change oil every 15,000 miles, every 6 months, or every 500 engine operating hours (whichever comes first) |
Please check the oil level regularly to ensure safe engine operation.
How to Change the Oil in a 6.7L Cummins Diesel Engine
Prepare the following:
- The recommended amount of diesel engine oil
- An oil drain pan
- A new oil filter
- Wrenches, rags
- Other specialized tools as specified in the vehicle manual
Procedure:
- Park the vehicle securely, shut off the engine, and allow it to cool.
- Remove the drain plug and allow the old oil to drain into the oil pan.
- After the oil has drained, remove the oil filter, making sure the O-ring on the old filter is also removed.
- Install the new oil filter (if possible, prefill the filter with a small amount of new oil).
- Add approximately 11 quarts of new engine oil initially.
- Start the engine, run it for about a minute to circulate the oil, then shut it off.
- Check the oil level with the dipstick and add oil as needed, up to the MAX mark.
- Check for leaks and ensure the drain plug and oil filter are tightened securely.
- Dispose of the used oil and old filter properly and take them to a recycling center.
Tip : After completing the oil change, always check again for leaks and ensure the drain plug and oil filter are securely tightened.
Common 6.7 Cummins Engine Oil Issues and Solutions
Oil Leaks
Check for leaks around gaskets, seals, and the oil pan. Loose bolts may only need tightening, but worn parts should be replaced to prevent further damage.
Excessive Oil Consumption
If your Cummins engine is losing oil rapidly, it could be due to worn piston rings, a faulty turbine seal, or deteriorating valve stem seals. A professional inspection is recommended.
Improper Oil Level
Low or high oil levels can cause pressure fluctuations, unusual noises, and potential engine failure. Always maintain the oil level within the recommended range.
Unusual Engine Noise/Pressure
These symptoms could indicate a clogged oil passage or oil pump failure. Addressing the issue early can prevent significant engine wear.
💡Performance Tip : For performance-oriented owners, EGR delete kits can reduce soot contamination in the oil, but note that these modifications may affect emissions compliance and warranty coverage.
Common Questions about 6.7 Cummins Engine Oil Maintenance
Conclusion
Using the right engine oil, maintaining the correct 6.7 Cummins oil capacity, and adhering to proper oil change intervals are crucial. Don't forget to account for the slight difference in oil levels between when you change the filter and when you don't, and make it a habit to check the dipstick regularly. By adhering to these practices, your 6.7L Cummins engine will remain reliable, efficient, and powerful for many years to come.
