Following the release of an all-new fourth generation for the 2019 model year, the 2021 Chevy Silverado 1500 receives a few small changes and updates. What’s more, Silverado diesel models received a price drop at the end of the 2020 model year production run, which then carried over to the 2021 model year. Now, 2021 Chevy Silverado models equipped with 4WD and the Duramax diesel engine option post lower fuel economy ratings when compared to similarly equipped 2020 model year vehicles.
Looking over the latest fuel economy figures, we see that the 2021 Chevy Silverado 4WD diesel posts one fewer mpg in the city, three fewer mpg on the highway, and one fewer mpg combined. Meanwhile, there are no fuel economy differences between the 2020 Chevy Silverado 1500 2WD Duramax and 2021 Silverado 1500 2WD Duramax.
| Rating | 2021 MY | 2020 MY | Difference |
|---|---|---|---|
| City mpg | 23 | 23 | - |
| Highway mpg | 33 | 33 | - |
| Combined mpg | 27 | 27 | - |
| Rating | 2021 MY | 2020 MY | Difference |
|---|---|---|---|
| City mpg | 22 | 23 | -1 |
| Highway mpg | 26 | 29 | -3 |
| Combined mpg | 24 | 25 | -1 |
For reference, the engine in question is the 3.0L I6 LM2 Duramax, which produces 277 horsepower at 3,750 rpm and 460 pound-feet of torque at 1,500 rpm.
We reached out to General Motors for an explanation as to why the 2021 Chevy Silverado 4WD diesel fuel economy numbers decreased compared to the preceding 2020 model year. Here’s their answer:
“The 4WD 3.0L configuration went up in its test weight class, which led to slightly reduced fuel economy to 22 city/26 highway/24 combined,” General Motors told GM Authority. “The 2WD configuration remains best-in-class with 23 city/33 highway.”
We followed-up by asking GM about the weight gain alluded to for the 4WD 3.0L configuration. General Motors responded by telling GM Authority that it had to do with “higher contented truck being tested based on production schedule.”
As such, these slightly lower fuel economy ratings would, in theory, not reflect any real-world fuel economy losses for customers.
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Comments
So now they line up with the Sierra’s rating, assuming it hasn’t dropped. Always seemed odd that the Silverado had a much better EPA rating.
Hmmmmm,,, very interesting! Sounds like a double-talk political type answer from GM! Why not a more in-depth factual explanatory answer from GM?
I’m getting more meaningful insight from reading some of the comments…..
And yes,,, even given some kentucky windage, IMO, a 3 mpg drop is significant as a consumer!!
3 miles-per-gallon is a drop of over 10-percent and this could make the difference in whether someone decides to buy the Chevrolet Silverado 4WD with optional Duramax diesel engine.
This has nothing dot do with actual real life mileage, this is epa estimate. They test differently. The article here is saying several pounds from additional features pushed the 4wd up a weight class and changes the DYNO settings. Actual mileage will varry greatly, as in the case where motortrend hyper miles at 55mph to get mid 40’s mpg with the truck
Why is it that the highway mpg difference between four-wheel drive and two-wheel drive trucks with gas engines doesn’t vary all that much, but it varies hugely with the diesel engine?
And with respect to the diesel engine trucks, what would highway mileage be for a four-wheel drive truck set at two-wheel drive? Would it be comparable to a two-wheel drive diesel truck, plus let’s say an extra mile per gallon due to the extra weight?
This is an EPA estimate you have to do the actual calculations
Making a 4 litre I6 diesel would It be a closer tow rating to 5.3 V8. If so should be offered in WT pickup etc. I think farmers and construction companies would love it.
Sounds like poor planning on GM’s part. You’d think they would say “hey we got the EPA testing one of our trucks next week let’s make sure it’s equipped properly because their results will be published and etched in stone about our trucks”! It’s total incompetence on GM’s part!! They need to get their Sh!t together!! Shameful!! I’m not buying their explanation.
GM explained the difference! No incompetence. They had to test a truck with more “options” because their production schedule (what they plan to build to meet demand) had heavier option loads. EPA requires option load to reflect actual production —– the company can only “play” with “estimates” so long, then has to face what’s really been built. We used to “restrict” sunroofs to an expensive package to keep its penetration lower (so it didn’t have to be included in the model tested). I would bet nothing actually changed year to year —- except the tested model.
More MPG insanity from the EPA and GM. How does Ram get away with posting the same identical MPG ratings for a regular cab Tradesman 4X4 with the 5.7 Hemi vs a fully optioned 4 door model that weights 500 LBS more with tires ranging up to 22″? I don’t see any difference over at Ford either. This is crazy beyond words. So GM has to account for every couple of pounds and tire sizes with way under rated MPG on it’s 4X4 diesel models but none of the others do? Is GM trying to reduce sales or is the EPA playing some kind of game with GM that doesn’t seem to affect any other company? It sounds to me like the EPA needs to drastically overhaul there super flawed way of calculating mileage and the car companies need to be more realistic on their trucks and SUV’s that can be ordered 50 thousand different ways.
Same EPA rules for everyone. Maybe RAM and Ford’s heavy loaded models have low enough penetration to be “shielded” by the lower equipped tested model.
A lot of the comments here are over thinking this. If the weight class went up if they claim, all they’ve done is under-rate the estimates for 4×4 trucks now. ESTIMATES. Your results may vary, even on a 2020 rated at 29mpg highway.
Actually, they now have the same rating as the 2020 Sierra with the 3.0 diesel, which is also up weight over the 2020 test for Silverado. Plenty of people with 4×4 2020s out there getting some great highway and average MPG numbers.
This is probably what got Ford on their 4×4 3.0 Powerstroke that is 25mpg highway vs. 29mpg for the 2wd.
EPA estimates have always been garbage anyways. Just look at how badly Ford was able to inflate their truck EPA ratings. GM trucks have always had conservative ratings. I regularly beat the EPA estimates for GM trucks I’ve driven. Can’t say that about the 2019 Ram 1500 I had. Those estimates were a complete joke. Just because the EPA rating changed for this truck doesn’t change a thing. They’re just using a heavier truck to use for EPA testing. The exact same truck as a 2020 model would get the same fuel economy despite a higher EPA estimate on the sticker.
Your results may vary by up to 7 MPG going from 2WD to 4WD when it’s a GM but at Ford and Ram those number variances shrink to 4 and 3 MPG when diesel engines are concerned. Mind you all of the other engines in the lineup vary by only 1 to 2 MPG when going from 2WD to 4WD. I see major flaws in how they calculate mileage ratings and the consumer is going to look at these crazy window stickers and want the one that gets higher mileage. GM loses again!
I own a 2020 Sierra 1500 crew cab 4×4 Duramax
I regularly get sub 8 liters per 100k on the highway… My best currently is 7.1…. I for sure could get sub 7L/100km. That’s going 110 KPH.. so that’s pretty decent if you ask me… ITS BETTER THEN THE OLD ASS CAR I WAS DRIVING LOL
I’m not sure why the MPG number would get worse……
There are good reasons for some people to want the diesel. But MPG (or kms/100) shouldn’t be one of them. My 2020 Silverado with the 2.7 gets about 8.5 litres per 100 at 110 kms per hour, and about 10 litres per 100 city.