What Kind Of MPG Does A 6.7 Cummins Really Get? Here's What Owners Say

Cummins turbodiesel inline six-cylinder engines have long been the backbone of heavy-duty Dodge Ram trucks. Since their launch back in 1989, the oil burners have gone on to provide muscle for Ram's 2500 and 3500 pickup truck lines across two different displacements: 5.9- and 6.7-liter. The 5.9-liter engines (5.9L 12V and 5.9L 24V) were produced between 1989 and 2007, generating 160-325 horsepower and 400-610 lb-ft. With this, a Dodge Ram 3500 could tow up to 13,700 pounds, while 3500 models were tow-rated at 16,250 pounds max.

The 6.7-liter Cummins turbodiesel inline six-cylinder engine didn't debut until January 2007, but was well worth the wait. Despite the increase in displacement and power output — up to 350 hp and 650 lb-ft at the time — Cummins claimed a 10% reduction in fuel consumption and lower emissions thanks to its adoption of the Selective Catalyst Reduction (SCR) emissions control technology. But more impressively, power has now been bumped to 430 hp and 1,075 lb-ft in the current-generation 6.7 Cummins, with towing capacity also rising to 36,610 pounds.

Between its capability, power, and longevity, the 6.7 Cummins undoubtedly appeals on many fronts. But just what kind of mpg does it really get? Well, official mpg figures aren't typically made publicly available for heavy-duty trucks such as the Ram 2500 and 3500, as they weigh above the 8,500-pound GVWR limit for current testing procedures. This means real-world fuel economy remains the only way to find out what the mpg of the 6.7 Cummins turbodiesel is. Hence, we've checked out online forums dedicated to 6.7-liter Cummins discussions, as well as websites like Fuelly and Car and Driver to see what people are getting. In its mpg tests, Car and Driver found the 6.7 Cummins offers between 14 and 20 mpg in combined city-highway driving.

According to owner reports online, the 6.7 Cummins turbodiesel engine will do up to 18 or more mpg in combined city-highway use. Posting on Reddit, some users said they were able to achieve 18 mpg on average. However, the general figures vary hugely from driver to driver. While some have reported averaging around 11 mpg many others found the 6.7 Cummins mpg to be fairly higher, with some even getting around 23-24 mpg. In their comment on the Ram 1500 Diesel forum, one owner said: "On the road, I see an average MPG that varies around 23 to 24 MPG unloaded and not towing. Typical driving is rural, with few stops and most roads 55 MPH and up."

Over on Reddit, some have reported achieving towing mileages of between 10 and 12 mpg. Overall, your 6.7 Cummins mpg will run between around 10 and 24 mpg, depending on several factors, including whether you have dually tires or have made modifications to the vehicle. Others include your driving habits, the terrain you're driving on, the speed at which you typically drive, and whether the truck is loaded or unloaded. Yet another factor that might affect your mpg figures is the type of engine under the hood, as the new 6.7-liter Cummins high-output turbodiesel is said to be more efficient compared with the older, standard output iteration of the 6.7-liter.