How Many Miles Can A 6.7 Cummins Last? (And Can You Get To 500k?)

The most common vehicles to have a 6.7 Cummins under the hood are heavy-duty RAM trucks, such as the Ram 2500 and 3500 pickups and chassis cab models. However, other pickup trucks are powered by Cummins diesel engines too.

There's no denying that the 6.7L Cummins diesel is a good engine. Cummins introduced its 6.7L turbo diesel in 2007 with 350 horsepower and 650 lb-ft of torque, a modest increase over the outgoing 325-horsepower 5.9 Cummins diesel engine with 610 lb-ft of torque. However, it provided substantially more torque than the gasoline-powered 5.7-liter HEMI provided as standard equipment in the heavy-duty 2007 Dodge Ram with its 375 lb-ft rating.

The 5.9 Cummins  are considered some of the best, however, 6.7-liter Cummins built between 2007 to 2015 are fan favorites as well. Horsepower and torque ratings for the 6.7 Cummins have steadily increased over the years. In recent years, RAM 3500 buyers could choose between the standard and high-output 6.7-liter Cummins diesel. Now, the heavy-duty 2025 RAM pickup line features the HO 6.7-liter Cummins with 430 horsepower and 1,075 lb-ft of torque as the only diesel engine option.

Owner reports of 6.7 Cummins diesel engines exceeding 200,000 and 300,000 miles are common. One owner of an 18-year-old 6.7 Cummins-powered truck with 211,000 miles, Witty_Ad4494, said on Reddit that their mechanic "says the motor will outlast the rest of the truck 5 times." Another user, poposheishaw, jokingly said that a 6.7 Cummins with "anything over 6,000,000 [miles] is probably too many."

Yes, the 6.7 Cummins turbo diesel engine is capable of lasting for 500,000 miles or more as long as it is properly maintained. While the High Mileage Club sponsored by Cummins currently has two entrants near the 500,000-mile mark, they're both 5.9 Cummins diesels. It's important to note that, with its 2007 introduction, the oldest 6.7 Cummins turns 18 years old in 2025, so even assuming 25,000 miles per year, it would only see 450,000 miles total.

Reddit user ExconHD points out that the engine itself "is strong," but poor maintenance, bad injectors, or a random broken bolt is what typically renders them inoperable before their time. Over8yted agrees that the 6.7 Cummins doesn't often succumb to wear and tear when properly maintained, but fuel-system maintenance, including replacing injectors, injector pumps, and the occasional turbo "are expensive and sometimes cost prohibitive."

Other than the failure of the diesel engine's peripheral parts, such as emissions systems, fuel delivery, and accessories, or a rare catastrophic engine failure, one other killer of the 6.7 Cummins is blowby, and it can be fixed. Blowby is caused by excessive wear in the cylinders, or carbon buildup in some cases, and will eventually happen to all engines with enough miles. If you're willing to rebuild the 6.7 Cummins if it reaches that point, it could last millions of miles.