2007.5-2009 Dodge 6.7L Cummins Engine Oil

Engine oil on the 2007.5-2009 Ram 6.7L Cummins

The 6.7L Cummins takes 12.0 quarts with the filter, which is three gallon jugs. The oil spec is API CJ-4, the low-ash category, because the diesel particulate filter cannot tolerate high-ash oil. CK-4 oils also qualify. Older CI-4 oils are not appropriate on a DPF-equipped 6.7L, so read the API category on the jug, not just the viscosity.

Fuel dilution and why oil choice matters

Active DPF regeneration uses late post-injection, and some of that fuel can end up in the crankcase. Signs are an oil level rising above the full mark, thin oil with a diesel smell, and lowered viscosity on oil analysis. It is worst with heavy idling, short trips and frequent regens. Ram's own diesel supplement lists 5% fuel dilution as acceptable, which is the number to judge an oil analysis against. The low-cost counter is a 5W-40 full synthetic CJ-4 or CK-4 and a shorter interval under the severe schedule. On heavily idled or towing trucks, Diesel Hub recommends an oil analysis 500-1,000 miles before the scheduled change and no more than 10 minutes of idle in any hour.

What we carry

• Hot Shot's Secret: Green Diamond full synthetic CK-4 in 5W-40 and 15W-40, Green Diamond 15W-40 semi-synthetic CK-4, Blue Diamond 5W-40 full synthetic CK-4 and Black Diamond Outlaw 15W-40 full synthetic CK-4, plus other grades (Green Diamond 10W-30 and 0W-20, Black Diamond Outlaw 10W-30) and the ADRENALINE R-Series racing oils. Additives include TBN Booster oil stabilizer, FR3 friction reducer and the Original Stiction Eliminator.
• Lucas Oil: 15W-40 CK-4, Synthetic 15W-40 CK-4, Synthetic Blend 10W-30 CK-4, Magnum High TBN 15W-40 (labeled CI-4), Heavy Duty and Synthetic Heavy Duty Oil Stabilizer, and TB Zinc Plus engine break-in additive.
• XDP: X-Factor high performance oil additive.

Picking the right jug

For routine changes on this truck, stay with the factory grades: 15W-40 above 0 F, or 5W-40 full synthetic for cold weather or year-round. The oil lines here also run other grades (0W-20, 5W-20, 10W-30, 20W-50 and the racing oils) because they cover many engines; those are not the factory call for this truck. Skip the CI-4 Magnum for this DPF-equipped engine. Additives are optional and do not replace the right oil or the change interval. When you drain it, the plug torques to 35 lb-ft.

Frequently asked questions

What oil does a 2007.5-2009 6.7L Cummins take?

API CJ-4 low-ash oil: 15W-40 above 0 F, or 5W-40 full synthetic for cold or all temperatures. CK-4 oils also qualify. Capacity is 12.0 quarts with the filter, and the interval is 7,500 miles or 6 months.

Can I run CI-4 oil in my 2008 Dodge Ram 6.7L?

No. Older CI-4 oils are not appropriate on any DPF-equipped 6.7L, and these trucks have a DPF from the factory. Use an oil labeled CJ-4 or CK-4. That is why we flag the Lucas Magnum High TBN 15W-40 above: it is labeled CI-4.

Is 5W-40 full synthetic worth it on this truck?

It is the factory grade for cold weather or year-round use. Switching to a 5W-40 full synthetic CJ-4 or CK-4 and shortening the interval under the severe schedule is also the low-cost counter to fuel dilution. If your truck idles a lot or tows, pair it with an oil analysis 500-1,000 miles before the change.

Not sure what fits? Call the shop at the number in the header, or use the fitment checker on any product page. We install everything we sell.