Average Fuel Economy of Duramax Diesel Engine Trucks

When it comes to hauling heavy loads and tackling tough terrain, it’s hard to beat a diesel-powered truck. For GM truck enthusiasts, the Duramax diesel engine has become synonymous with power, performance, and surprisingly good fuel economy.

With the price of fuel these days, getting more miles per gallon of diesel is more important that it used to be. Let’s look at the real-world gas mileage that can be expected from five of the most popular Duramax-equipped trucks broken down by year.

Duramax diesel MPG

See Also: 10 Best Diesel Engines (Duramax vs Cummins vs Power Stroke)

Duramax MPG for 5 Most Common Trucks

Below are 5 top-selling trucks powered by Duramax diesel engines. Because manufacturer based MPG numbers are usually unrealistic, the fuel mileages shown below are taken from hundreds of actual owners of the vehicles themselves, millions of miles driven, and actually putting the trucks through typical days of work (courtesy of Fuelly.com).

Note: Obviously, the actual fuel economy achieved is based on many factors (speed, driving style, weight, towing, etc.) so your results may vary but this should give you a good idea of “real-world” usage.

#1 – Chevrolet Silverado 2500HD

Chevy Silverado 2500HD Duramax Diesel

YearAverage Miles Per GallonYearAverage Miles Per Gallon
200115.4 MPG200215.0 MPG
200314.9 MPG200414.3 MPG
200513.9 MPG200614.3 MPG
200714.6 MPG200814.5 MPG
200913.4 MPG201014.7 MPG
201113.7 MPG201213.3 MPG
201314.9 MPG201414.3 MPG
201514.2 MPG201614.3 MPG
201714.3 MPG201813.8 MPG
201914.5 MPG202013.1 MPG
202112.5 MPG202210.6 MPG
202313.5 MPG202414.0 MPG

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#2 – GMC Sierra 2500HD

GMC Sierra 2500HD Duramax Diesel

YearAverage Miles Per GallonYearAverage Miles Per Gallon
200114.2 MPG200215.0 MPG
200315.2 MPG200415.5 MPG
200513.6 MPG200614.7 MPG
200714.3 MPG200814.4 MPG
200914.6 MPG201015.0 MPG
201113.9 MPG201213.7 MPG
201313.4 MPG201413.7 MPG
201513.9 MPG201614.4 MPG
201714.2 MPG201815.3 MPG
201914.4 MPG202014.3 MPG
202113.1 MPG202212.1 MPG
202315.6 MPG202413.8 MPG

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#3 – GMC Sierra 3500HD

GMC Sierra 3500HD Duramax Diesel

YearAverage Miles Per GallonYearAverage Miles Per Gallon
200713.6 MPG200813.3 MPG
200915.1 MPG201013.2 MPG
201113.7 MPG201213.3 MPG
201312.5 MPG201412.2 MPG
201514.3 MPG201612.6 MPG
201713.3 MPG201811.8 MPG
201911.2 MPG202013.5 MPG
202113.8 MPG202210.9 MPG
202312.1 MPG202412.4 MPG

#4 – Chevrolet Colorado

Chevy Colorado Duramax Diesel

YearAverage Miles Per GallonYearAverage Miles Per Gallon
201620.8 MPG201720.9 MPG
201819.8 MPG201919.0 MPG
202019.6 MPG202119.8 MPG
202218.9 MPG202319.6 MPG

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#5 – GMC Canyon

GMC Canyon Duramax Diesel

YearAverage Miles Per GallonYearAverage Miles Per Gallon
201621.1 MPG201722.7 MPG
201821.4 MPG201919.9 MPG
202020.2 MPG202119.6 MPG
202219.6 MPG202318.6 MPG

Brief History of the Duramax Engine

Duramax engine fuel economy

When GM was losing ground to competitors in the late 1990s, they knew they needed a powerhouse diesel engine to get back in the game. Enter the Duramax – a new 6.6-liter turbocharged V8 that would give drivers a one-two punch of performance and fuel efficiency.

Developed hand-in-hand with diesel experts Isuzu, this engine was the first of its kind with high-pressure common-rail direct injection, vaulting GM diesel trucks into the 21st century.

Since its debut in 2001, the Duramax has undergone evolution after evolution to better serve GM truck loyalists. Updates over the years have pumped up the power and torque while keeping emissions in check and improving MPG.

The recent 2017 L5P Duramax is a crowning achievement as the two millionth unit built – and the most muscular yet, churning out a stunning 445 horsepower and 910 lb-ft of torque.

For GM enthusiasts seeking maximum capability with every turn of the key, the Duramax delivers the goods. This powerplant helped put the manufacturer back in the game. Duramax engines are commonly found in heavy-duty pickup trucks, as well as mid-size pickups, full-size vans, and even SUVs.

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Mark Stevens


  1. Have a 2002 GMC 2500 HD Duramax Long Bed 4X4 Extra Cab. Bought @90K, Now 155K. Gets 17 mpg mixed local, 19-20 mpg on Hwy @70 mph and 10-11 mpg @65 mph towing 6000 lbs Travel Trailer. Truck is Stock.

  2. Have a ’19 Silverado with 6.6 and have to take it easy to get anywhere near the 20 mark. Usually in the low 16’s. Just pulled a light trailer (approx. 3000 lbs.) right at 100 miles and taking it really easy best I can get is just topping 14. Truck seems gutless with only 17000 miles. Dealer keeps telling me it will get better with more miles. I think they are just pacifying me to get rid of me.

  3. I am only getting 14.5 mpg at 70 miles per hour empty.I drive a 2020 3500 dually it only has 4000 miles. Will my fuel mileage improve?

    1. I have a 2021 chevy 3500hd dually long bed and my average mileage is also 14.5 with no load. That is running at 75 mph. I have gotten better mileage at 65 mph (around 17) but driving at that speed unloaded doesn’t work for me. I have a 16k 5th wheel that I have not towed yet so it will be interesting to see how that works out. In 50 mile average I have gotten as high as 21.6.

  4. I have a 2018 with 32,000 on it now, I’m a kid at heart and drive like a teenager sometimes (most of the time), can’t help it with 450 hp, I don’t seem to get any consistency, I have gotten 12-23 driving the same route and average speeds on the way to work. It smells hot some days and gets on the low end, I think it’s the exhaust emission.
    What is consistent is if you stay 65 MPH or under on the highway you can stay above 20 MPG, even towing light loads, sleds or side by side, 13,000 lb tractor and trailer takes it down to 13 on highway.

  5. We have a 2012 duramax. We get 17 mpg towing or not. It has 300,000 miles on it. One owner. When should we change the belts and hoses? Gail

    1. While I haven’t seen the owner’s manual for this exact vehicle, it’s very likely that you’re past the service life of the vehicle, meaning that the manual can’t tell you this info anymore. Since parts deteriorate with age, the interval between replacements may be shorter now than when the truck was younger. It is best to have a mechanic you trust examine the car thoroughly for cracked, brittle, or leaky parts at every oil change, if not more frequently.

  6. Hey I have a 2003 6.6 that went threw similar problem. The injector’s were covered by the factory I think Up to 200k miles might want to look into it also change fuel filter from (original) 5 miconrs to New 2 mic will avoid this from happening again soon good luck

  7. I have a 2016 Chevrolet 2500HD 6.0 gas, Crew cab, 4X4, with a 600 pound lift gate. I usually get about 12.5 on the highway and 11 around town. Pulling my 3000 pound trailer from Florida to Texas and back, I averaged 9.2 mpg on the interstate. The truck only has 35k miles. It’s bone stock now, but I’m thinking about putting headers and a less restrictive breather on it.

    1. Thanks for an honest statement of MPG. I can’t believe that anybody is getting 14 MPG plus pulling a travel trailer

  8. I have a 2017 Chevy Colorado 2.8 L. had for 3 years now and live in Chicago, been driving highway and city going to work everyday, and I average 25.9 on both city and highway miles… I dont know if the cold air intake is why but I get great gas mileage.

    1. How about towing milage. My 09 gmc duramax 4dr long box with a tuner and bigger exhaust gets 22-24 mpg at 60 mph 20-22 mpg at 70 unloaded and 18-20 mpg at 80 mph. Towing up to 10k lbs i got 12-14 mpg between 60 and 80 mph. Hauling 15k lbs of hay bumper pull i averaged 10-12 mpg doing 60-70 mph. 209k miles on it now. My mother had it with bully dog system on it from about 100k -163/169k miles which is when I bought it from her. I pulled a 76 k20 long box reg cab loaded with furniture in both truck boxes from nd to Michigan got 16-17 mpg.

  9. I Just Bought a 2500 SLZ 150 miles on it I’m Just over 12 MPG Hope it Keeps Going up!

  10. I have a 2020 Denali 3500 Duramax with a new 10 speed Allison love it empty I get 21 to 23 pulling on 16,000 pound fifth wheel I’m getting anywhere from 12 1/2 to 9 1/2 depending on the hills and train

    1. Is your truck a Dooley I’m fixing to purchase two of them to start pulling campers for hire was kind of curious about what type of fuel mileage they would get

  11. I had 2500 ram 2wd found changing to dual exhaust & aftermarket air filter got me almost 22 mpg with 2005 5.9.

  12. Curious what the results are with the camper. I have a travel trailer and looking at moving from a tundra to the 2500 Duramax. Getting 6.8@ 65mph now in the Tundra.

    1. I had a 2004 Chevy Duramax and got about 19 empty over the road. I also had a 2012 GMC Duramax. I hauled an 8500 lb 5th wheel from San Antonio to Grand Canyon Through Utah to Yellowstone to the Black Hills And back to TX. 6000 miles. Got an average of 11 mpg. Getting ready to buy another GMC Duramax. To me there is no other choice. I really didn’t feel the trailer behind me at anytime through the mountains etc. Hardly ever got above 1700 rpm. Hope that helps.

  13. I have a 2015 2500HD LTZ Double Cab. I hate the Double Cab. On my meter of the last 50 miles I have a best of 27.5. Pulling my trailer I would get 10 to 12. I never topped a hill under 60 MPH. My truck doesn’t like the cold weather. It drops to 13 to 17 around town and even trips of 200 miles. I have 62000 miles on the truck.

  14. We have a 2002 GMC Duramax, now with 880,000 miles. Three times dealerships and transmission shops condemned the transmission, and 3 times we found they were incorrect. We have changed injectors on the engine once, and cleaned them twice. Our diesel mechanic recommends we dump a half quart of transmission fluid into the fuel at every fill up to help keep the injectors clean.

    1. Very cool. These engines are great. Hoping you hit 1 million. I should create a poll someday for owners of Duramax trucks.

      1. I have a 2011 4×4 2500 LTZ Crew Cab that I lifted 3 inches to run 14×35 tires on it , installed Rhino bumpers, line bored the exhaust to run a 4 inch straight pipe ,took out the EGR pipe, cold air intake and we installed a programmable 5 position chip box in it. Has so much power in stock mode I can smoke the tires ,beat many performance cars in a race ,pull a 38 ft Donzi on its trailer Or a loaded semi pretty fast
        It has 215,000 miles on it , I drive it daily average in town & interstate which averages 16.4mpg, on the interstate at 70 mph I get 18-19 mpg or towing a 15000lb boat get 12-13 mpg
        We did the same to my buddies truck that is stock and he gets 10 mpg more than I do

    1. Hello all, I have a 02 hd2500 4×4 long box crew with the duramax. I purchased back in 02 used with 30k miles. I love this truck, I have 230k and it just went to shop yesterday for first issue. It is smoking blowing unburdened fuel out exhaust. I was getting 19mph when empty and never below 16 on a normal pull. If you keep it under 72mph. Now around 16 to 14. Time for surgery, lol. Was told 3,500 to 4,500 for full injection rebuild. Will see.

  15. I have a GMC Sierra SLE 2007 3/4 ton (2500)LBZ 6.6 Duramax with a 6 speed Allison Transmission. Pulling a huge load at 50mph in 4 gear I get about 10 mpg. Pulling a medium load in 5th gear at 62mph I get about 14mpg. Empty on the highway driving 63mph I get about 20mpg. Empty at 70mph I get about 18mpg. I have 235K on the engine. It still runs great! The size of the load and amount of wind can and will make a difference. Change oil & filter every 7500 with Valvoline Blue Extreme. Change the transmission filters, fluid and the pumpkins every 100K with Amzoil synthetic recommended viscosity’s. Rocker panels are starting to rust. ($5K to repair at the bodyshop) I was in the dealership today to price out a new one, about $60K for a GMC Sierra SLE no leather crewcab and a long bed. Thinking about it or just purchasing another used GMC duramax. I don’t think I would ever go back to a gas engine, I love the power of the diesel!

    1. My 2019 2500 HD Duramax pulling an empty 8 x 20 cargo trailer, at 70-80 mph, gets around 9-10 mpg. Terrible! Going back to gas.

      1. …Should consider slowing down to around 65 mph. I have a 2018 GMC Sierra Denali loaded with the 6.6 Duramax diesel with 13,000 miles on it and I’m averaging 22.4 mpg (when using the cruise control and not towing anything). Will see whaI I average when towing my 9,000 lb 5th wheel camper. i think I’ll still be happy with my baby.

        1. Curious what the results are with the camper. I have a travel trailer and looking at moving from a tundra to the 2500 Duramax. Getting 6.8@ 65mph now in the Tundra.

    2. I have a twin to your truck. Mine is pure stock everything. How do you achieve the mpg’s you mentioned? Pulling a large load I get 10.5 or so, empty I get 14.9.

  16. 2019 duramax crewcab srw getting 24mpg hwy, level road 65mph Standard factorry equipment? Encouraging to know if that is true. Can changing filters, exhaust or anything else increase mpg?

    1. So much of MPG is based on driving style but yes, I do believe you can increase mileage from a better intake, a more free-flowing exhaust (sometimes), or custom fuel mapping. If someone really wanted to, I bet they could get close to 30 MPG with a Duramax.

      1. Stock 2019 2500HD have gotten 30mpg over 100 miles and average on the tank was 25 mpg of 720 miles

  17. The results above are based on “real-world” scenarios of thousands of drivers so there’s no way to know but I’d assume most are running their trucks stock or close to it.

  18. I was hoping somebody had tried success getting better mileage. I’m picking up a 2008 with 220k on it this week. If you don’t mind my asking, what year is your truck, Jim?

    1. I had a 2008 for 8 years…..always 17 mph or above when towing at 65 or 70 mph, about 12k lbs of tow wieght…..at 70 cruising no trailer…. i got as high as 24 mpg.

  19. I have a 2011 when it was new I could get close to that. Now after a few software updates, 16 best.

    1. I put Michelin LTX tires on my 2018 Duramax and get 23-24 MPG running 65. That’s an increase of 4-5 MPG over the stock Goodyears that came on it. Tire pressure plays a big role along with not flying out of the hole and not passing other vehicles. I run 70 lbs in the front and 75 in the rear tires.

  20. While driving in the right most lane on level highway at 65 miles per hour I can pull 24 mpg with the Duramax diesel 6.6L in my Silverado 2500HD truck.

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