The 2018 6.7 Cummins diesel engine is one of the most powerful and reliable heavy-duty engines used in Ram 2500 and 3500 trucks. Known for its massive torque and towing capability, it requires proper lubrication to maintain long-term durability.
Choosing the correct oil type, maintaining proper oil levels, and following service intervals is critical for preventing wear, protecting turbo components, and ensuring optimal diesel performance.
2018 6.7 Cummins Oil Type
The recommended engine oil for the 2018 6.7 Cummins is 15W-40 diesel-rated oil for warm climates and heavy-duty use. In colder regions or for improved cold starts, 5W-40 full synthetic diesel oil is preferred.
All oil used must meet CJ-4 or CK-4 API specification to ensure proper protection of the turbocharger, fuel system, and emissions components.
Best Choice: 5W-40 full synthetic CK-4 diesel oil provides the best balance of cold-start protection and high-temperature stability.
2018 6.7 Cummins Oil Capacity
Oil capacity remains consistent across most 2007.5–2018 Cummins engines. Always check dipstick after filling to avoid overfilling or underfilling.
Oil Filter Information
- OEM Filter: Fleetguard LF16035 / Mopar Equivalent
- Aftermarket Options: Wix, Baldwin, Donaldson, Fram
- Recommendation: Replace oil filter at every oil change
Oil Change Interval
Oil change intervals depend on usage, towing load, and driving conditions. Diesel engines under heavy load require more frequent maintenance.
2018 6.7 Cummins Oil Change Cost
- DIY Oil Change: $100 – $180
- Independent Shop: $180 – $300
- Dealership Service: $300 – $450
Common Oil-Related Problems
- Turbo wear from low-quality oil
- Oil dilution from EGR system
- Overheating under heavy load
- Oil leaks from seals
- Dirty oil causing injector strain
Maintenance Tips for Longer Engine Life
- Use only CK-4 or CJ-4 certified diesel oil
- Check oil level frequently during towing
- Replace oil filter every service
- Avoid extended oil change delays
- Monitor oil temperature under load
- Inspect for leaks regularly
Frequently Asked Questions
What oil does a 2018 6.7 Cummins take?
It uses 15W-40 diesel oil in warm climates and 5W-40 full synthetic in colder conditions.
How much oil does a 6.7 Cummins hold?
The 2018 6.7 Cummins holds approximately 12 quarts with oil filter change.
How often should oil be changed?
Every 7,500–10,000 miles depending on driving conditions and load.
What happens if wrong oil is used?
Using incorrect oil can reduce engine life, increase wear, and damage turbo components.
Final Thoughts
The 2018 6.7 Cummins is a high-performance diesel engine that demands proper oil maintenance. Using high-quality 15W-40 or 5W-40 CK-4 oil and following correct service intervals ensures maximum durability, towing power, and long engine life.
Quick Summary
- Oil Type: 15W-40 / 5W-40 Diesel Oil
- Capacity: 12 Quarts
- Change Interval: 7,500–10,000 Miles
- Best Option: Full Synthetic CK-4 Oil