How many miles per gallon does a 2013 6.6 Duramax get?
In typical use, a 2013 Duramax 6.6L diesel in Chevy Silverado 2500HD or GMC Sierra 2500HD returns roughly 15 miles per gallon in city driving and about 20–21 mpg on highways, with a combined average around 17–18 mpg. The exact figure depends on drivetrain, cab/bed configuration, and how much weight is being carried or towed.
What the numbers mean
The Duramax LML engine powering the 2013 heavy‑duty pickups was designed for pulling power and long-distance efficiency. EPA fuel economy figures are determined under standardized testing and can vary depending on drivetrain (2WD vs. 4WD), body style, tire size, and axle ratios. Real‑world results can diverge from these estimates based on towing, payload, terrain, and driving habits.
EPA ratings by common 2500HD configurations
These estimates reflect U.S. EPA ratings for 2013 Silverado/Sierra 2500HD models with the 6.6L Duramax diesel and a six‑speed automatic, focusing on typical cab/bed setups.
- Two‑wheel drive (2WD) versions with standard cab or crew cab and standard bed: roughly 15 mpg city and about 21 mpg highway; combined around 17–18 mpg.
- Four‑wheel drive (4WD) versions: roughly 15 mpg city and about 20 mpg highway; combined around 17–18 mpg.
EPA ratings can vary by exact cab/bed configuration, tire size, and axle ratios. Heavier or more aerodynamically challenged setups may fall outside these ranges.
Bottom line: these numbers provide a baseline, but real performance will depend on how the truck is equipped and used.
Real‑world fuel economy
Owner‑reported ranges and typical driving scenarios
In everyday driving without heavy towing, many owners report combined mileage in the mid‑to‑upper teens. When towing or hauling heavy loads, combined mileage commonly falls into the low‑to‑mid teens. On long highway trips with light loads and steady speeds, highway economy can edge into the low 20s for some drivers, though most report closer to 18–20 mpg overall.
- Typical daily driving with moderate payload: about 16–18 mpg combined.
- Heavier towing or payload increases: roughly 12–16 mpg combined, depending on trailer weight and terrain.
- Long highway cruising with light load and efficient speed: can approach 20–22 mpg for some drivers.
These figures illustrate how much real‑world results can diverge from EPA estimates based on usage patterns, maintenance, and driving conditions.
Summary
The 2013 Duramax 6.6L in heavy‑duty pickups typically delivers about 15 mpg in city driving and 20–21 mpg on the highway, with a combined figure around 17–18 mpg for common 2500HD configurations. Actual performance varies widely due to drivetrain, payload, towing, and driving habits. For buyers or owners, the best estimate comes from considering your typical use case and factoring in potential towing and load scenarios.
