For diesel truck owners, understanding fuel mileage is crucial. Whether you’re a seasoned trucker or considering purchasing a diesel pickup, fuel economy directly impacts your operating costs and overall vehicle efficiency. While light-duty trucks often have readily available MPG estimates, the landscape becomes less clear with heavy-duty (HD) diesel trucks. This guide dives deep into Diesel Truck Fuel Mileage, exploring factors that influence it, comparing HD and light-duty options, and highlighting models known for their efficiency.
Understanding Diesel Truck Fuel Economy
Fuel economy, often measured in miles per gallon (MPG), is a critical consideration for any vehicle, but especially for trucks known for their power and capability. For diesel truck owners, MPG translates directly into savings at the pump and extends the range between refuels. Light-duty trucks, with a gross vehicle weight rating (GVWR) under 8,500 pounds, are mandated by the Environmental Protection Agency (EPA) to undergo certification and provide estimated fuel economy figures, typically displayed on window stickers and in online reviews. However, this requirement doesn’t extend to heavy-duty trucks, making it harder to directly compare their MPG ratings.
Several factors play a significant role in determining a diesel truck’s fuel economy:
- Vehicle Weight: Heavier vehicles inherently require more energy to move, thus impacting fuel efficiency. HD trucks, built for tougher tasks, are naturally heavier than light-duty models, influencing their MPG.
- Vehicle Condition and Age: Regular maintenance is paramount for optimal fuel economy. Worn-out components, neglected servicing, and the general wear and tear associated with age can all degrade a truck’s MPG.
- Stock vs. Modifications: Factory settings are designed with a balance of performance and efficiency. Modifications, particularly those not focused on fuel economy, can alter airflow and engine performance, potentially increasing or decreasing MPG. Aftermarket diesel parts designed for efficiency, however, can improve fuel economy.
- Driving Habits: Aggressive driving, frequent hard acceleration, and excessive braking consume more fuel. Smooth, consistent driving at moderate speeds is the most fuel-efficient approach.
- Driving Environment and Terrain: City driving with stop-and-go traffic is less fuel-efficient than steady highway cruising. Hilly or mountainous terrain also demands more fuel compared to flat roads.
- Towing and Hauling: Diesel trucks are built for work, and towing or hauling heavy loads significantly increases engine workload and fuel consumption.
Heavy-Duty Diesel vs. Gas Truck MPG
While HD truck manufacturers aren’t obligated to publish fuel economy figures, independent organizations like Consumer Reports and Car and Driver conduct real-world testing to provide data. Generally, heavy-duty diesel trucks tend to have slightly lower MPG ratings compared to similarly sized gasoline-powered HD trucks. This is primarily due to the heavier weight of diesel engines and HD truck components. However, diesel engines often compensate with superior torque and towing capability, and for many users, the trade-off is worthwhile.
Top Heavy-Duty Diesel Trucks by MPG
It’s important to remember that MPG figures for HD trucks are often estimates based on testing and real-world driver reports. Actual mileage can vary significantly based on the factors mentioned earlier. Here’s a look at some top HD diesel trucks and their approximate MPG ratings:
#5) Chevy Silverado 2500 HD & GMC Sierra 2500 HD – 14.3 MPG
The Chevy Silverado 2500 HD and its closely related counterpart, the GMC Sierra 2500 HD, utilize a robust 6.6-liter V8 Duramax diesel engine paired with a 10-speed automatic transmission. Car and Driver’s testing indicates around 18 MPG in city driving and 21 MPG on the highway for the diesel Silverado 2500HD. However, real-world data from Fuelly, which aggregates driver-submitted fuel economy logs, shows a 2024 Chevy Silverado 2500 HD with the 6.6L Duramax averaging closer to 14.3 MPG.
#4) RAM 2500 – 15.9 MPG
The RAM 2500 boasts a powerful turbocharged 6.7-liter Cummins diesel engine known for its impressive torque output. Current models are estimated to achieve around 19 MPG in the city and 24 MPG on the highway. Fuelly’s data for the 2023 RAM 2500 with the 6.7 Cummins diesel aligns closely, reporting an average of 15.9 MPG, tying with the Ford F-250 for diesel MPG in this category.
#3) Ford F-250 Super Duty – 16.1 MPG
The Ford F-250 Super Duty is equipped with a turbocharged 6.7-liter Powerstroke V8 diesel engine, making it a formidable workhorse with significant horsepower and torque. Car and Driver’s evaluations suggest approximately 20 MPG on the highway and 15 MPG overall. Recent Fuelly statistics for the 2023 Ford F-250 Powerstroke 6.7L diesel indicate an average of 16.1 MPG.
Light-Duty Diesel Trucks: A Vanishing Breed with Impressive MPG
Historically, major truck manufacturers offered smaller diesel engine variants in their light-duty pickup trucks. However, diesel options in light-duty trucks have become increasingly scarce. GM discontinued the Duramax I4 engine in the GMC Canyon in 2022, and Ford no longer offers a Powerstroke diesel for the F-150. While gasoline engines have advanced significantly in power, light-duty diesel engines once held a strong position for fuel efficiency.
Leading Light-Duty Diesel Trucks for Fuel Efficiency (Past Models)
Although new light-duty diesel trucks are rare, some recent models stood out for their fuel economy:
#2) Ram 1500 EcoDiesel – 22.1 MPG
Ram previously offered the EcoDiesel engine in their 1500 series but discontinued this option in January 2024. The final diesel offering for the Ram 1500 was the 3.0-liter V-6 EcoDiesel, available in the 2023 model. Fueleconomy.gov estimates for diesel-powered Rams were around 21 MPG city and 29 MPG highway, though all-wheel drive slightly reduces these figures. Fuelly data for the 2023 Ram 1500 with the 3.0 EcoDiesel shows an average of 22.1 MPG, highlighting its fuel-efficient nature for a diesel truck. However, the EcoDiesel produced 260 hp and 480 lb-ft of torque, less powerful than larger HD diesel engines like the Ford Powerstroke 6.7L with 500 hp and 1,200 lb-ft of torque.
#1) Chevy Silverado / GMC Sierra 1500 3.0L Duramax – 23.2 MPG
The 3.0L LZ0 turbodiesel Duramax engine , known as the “Baby Duramax,” has been available in the Chevrolet Silverado and GMC Sierra 1500 since the 2023 model year and is celebrated for its fuel efficiency. It earned the top spot in “Which Diesel Truck Gets the Best MPG” comparisons, with EPA estimates of 23 MPG city and 33 MPG highway. Real-world Fuelly averages for the Chevy Silverado 1500 with the 3.0L LZ0 are around 23.2 MPG, and the GMC Sierra 1500 slightly edges it out at 23.7 MPG. This engine also delivers a respectable 305 horsepower and 495 lb-ft of torque, an upgrade from the previous 3.0L LM2 Duramax (277 horsepower and 460 lb-ft of torque) found in 2019-2022 models, which averaged 22.5 MPG on Fuelly.
Calculate Your Diesel Truck’s Real-World MPG
For older diesel trucks, factory EPA ratings may no longer be accurate due to wear and tear. You can easily determine your truck’s current fuel economy with a simple calculation:
- Full Tank: Fill your diesel tank completely.
- Record Gallons: Note the exact number of gallons required to fill the tank.
- Reset Trip Odometer: Set your trip odometer to zero.
- Drive a Distance: Drive a typical extended distance for your regular use.
- Record Mileage: Note the mileage reading on your trip odometer at the end of your drive.
- Divide Miles by Gallons: Divide the total miles driven by the number of gallons it took to refill the tank.
This calculation provides your truck’s MPG for that driving cycle. For instance, if you drove 250 miles and it took 12 gallons to refill, your MPG is approximately 20.8 (250 miles / 12 gallons). Remember that MPG can fluctuate based on driving conditions and usage. Performing this test multiple times under various conditions will give you a more comprehensive understanding of your truck’s average fuel economy.
To enhance your diesel truck’s fuel mileage and overall performance, consider upgrading with quality aftermarket parts from ProSource Diesel. We offer a wide range of diesel truck parts for Powerstroke, Cummins, and Duramax engines. ProSource Diesel is the trusted source for repair shops and diesel enthusiasts seeking reliable and hard-to-find diesel parts and kits.
