What is the gas mileage on a 2500HD 6.6 gas?
The straight answer is: there isn’t a 6.6-liter gasoline engine in the 2500HD. The 6.6 designation in GM’s lineup is tied to the Duramax diesel. Gas-powered 2500HD models typically used a 6.0-liter V8, and fuel economy varies widely by year, drivetrain, payload, and driving style. Expect roughly 12–15 mph in the city and 17–20 mph on the highway for a typical 2WD setup, with a bit lower numbers for 4WD or when towing.
More context: The “6.6” label often causes confusion because it appears in discussions of GM’s diesel lineup (Duramax 6.6L) rather than the gasoline option. This article breaks down what to expect from the gasoline-powered 2500HD, how EPA ratings can vary, and practical tips to maximize mileage.
Engine options and what the 6.6 label actually means
The Chevrolet Silverado 2500HD’s gasoline option does not use a 6.6-liter engine. The 6.6-liter displacement is associated with GM’s diesel family (Duramax). The gasoline-powered 2500HD most commonly used a 6.0-liter V8 (often marketed as Vortec 6000), paired with a 4-speed automatic in older generations and later variations with different transmissions. If you’re chasing a 6.6L gasoline variant, you’re likely running into a mislabel or a misunderstanding of the engine family.
Typical gasoline-miles-per-gallon for a 2500HD with a 6.0L V8
Below is a general guide for common drivetrain configurations. Exact EPA numbers vary by year, axle ratio, tire size, and whether the vehicle is empty or towing.
- Two-wheel drive (2WD) with the 6.0L V8: approximately 12–15 mpg in city driving and 17–20 mpg on the highway.
- Four-wheel drive (4x4) with the 6.0L V8: approximately 11–14 mpg in the city and 16–18 mpg on the highway.
In real-world use, numbers tend to sit toward the lower end of these ranges when towing, hauling, or operating under heavy payload conditions. They can improve slightly with lighter loads and steady highway driving.
Model-year, drivetrain, and configuration considerations
EPA fuel-economy ratings exist for many model years, but the heavy-duty segment doesn’t always publish uniform numbers across every year and trim. For a precise figure, check the EPA’s fuel economy website or the exact window sticker for the specific year, drivetrain (2WD vs. 4WD), axle ratio, and tire size.
Factors that commonly influence mpg across years and configurations include the following.
- Higher numerical axle ratios, which are common in towing-focused trucks, typically decrease mpg, especially in city driving.
- Transmission type and gearing can influence efficiency, with newer or differently geared transmissions sometimes improving highway fuel economy slightly.
- Actual payload and towing weight have a large impact; heavier loads drastically reduce mpg compared with light-duty operation.
Conclusion: The fuel economy you experience depends on how you use the truck, not just the engine’s displacement.
Tips to maximize fuel economy on a gasoline 2500HD
Whether you’re using a 2WD or 4x4 gasoline-powered 2500HD, a few practical steps can help you get closer to the upper end of the typical mpg range for this class of truck.
- Keep tires inflated to the recommended pressure; underinflation increases rolling resistance and reduces mpg.
- Use cruise control on highways to maintain steady speeds and minimize aggressive accelerations.
- Plan efficient routes and avoid unnecessary detours or heavy stop-and-go traffic when possible.
- Limit payload and towing when not needed for workdays to improve fuel economy.
- Perform regular maintenance (air filters, spark plugs, fuel system upkeep) to maintain optimal engine efficiency.
Conclusion: While the 2500HD is designed for payload and torque, mindful driving and routine maintenance can help you approach the higher end of the fuel-economy range for the gasoline variant.
Summary
In short, there is no 6.6-liter gasoline engine offered in the Chevrolet Silverado 2500HD; the 6.6L designation belongs to the diesel Duramax family. For the gasoline 6.0L V8, typical mpg figures fall around 12–15 mpg in city driving and 17–20 mpg on the highway for 2WD models, with 4x4 configurations generally lower. Exact numbers depend on year, drivetrain, axle ratio, tires, and payload. For precise ratings, consult the EPA data for the specific model year and configuration you’re considering.
Bottom line: if you’re shopping for a 2500HD with a “6.6 gas” label, verify whether the vehicle has the 6.0L gasoline engine or a Duramax diesel, and check the exact EPA ratings for the year and configuration to set accurate expectations about fuel costs.
