One of the major highlights of the redesigned full-size GM SUVs, the 2021 Chevrolet Tahoe and Suburban and the 2021 GMC Yukon and Yukon XL, is the newfound availability of a turbo-diesel engine, a 3.0-liter Duramax inline-six (borrowed from the Silverado/Sierra pickups). Now we have the fuel economy estimates for the new diesel as calculated by the EPA, and as expected they represent a significant improvement over the next-most-efficient engine, the 5.3-liter V8.
The 2021 Chevrolet Tahoe 2WD is 21/28 mpg city/highway and 24 mpg combined. The 4WD Chevrolet Tahoe diesel is 20/26 mpg and 22 mpg combined. That’s a big gain over the Tahoe with the 5.3-liter V8, which carries EPA estimates of 16/20 mpg city/highway and 18 mpg combined (2WD or 4WD).
The larger Suburban with 2WD and the diesel engine nets EPA estimates of 21/27 mpg city/highway and 23 mpg combined. Compare that to 16/20 mpg and 18 mpg combined for the Suburban with the 5.3-liter V8.
With 4WD, the 2021 Suburban diesel’s figures are 20/26 mpg city/highway and 22 mpg combined. Again, that’s significantly better than the 4WD Suburban 5.3-liter V8, which gets 15/19 mpg and 17 mpg combined.
Over at GMC, the Yukon 2WD’s highway and combined estimates are 1 mpg less than those of its Chevy sibling, at 21/27 city/highway and 23 mpg overall. The Yukon XL 2WD has the same EPA numbers as the smaller Yukon. EPA numbers for the 4WD GMCs, both Yukon and Yukon XL, are 20/26 mpg city/highway and 22 mpg combined.
Looking at the GM SUVs’ nearest rival, the Ford Expedition (powered by a 3.5-liter turbo V6) is rated at 17/23 mpg (RWD) and 17/22 mpg (4WD). The larger Expedition Max is 17/22 mpg (RWD) and 16/21 mpg (4WD).
GM’s Duramax diesel cranks out 277 horsepower and 460 lb-ft of torque, and carries maximum towing ratings of 8,000 pounds with the Suburban and 8,200 pounds with the Tahoe (RWD). It’s a $995 option over the 5.3-liter V8 on most trim levels, but in the High Country, which comes standard with the 6.2-liter V8, opting for the diesel nets buyers a $1,500 credit.