It’s been just about a year since General Motors pulled the cover off their latest full-size SUV models. In the time since, the automaker has shared just about everything we’d like to know about these modern land-yacht equivalents. One of the only major things left up in the air at this point was the fuel economy ratings for the 3.0L Duramax diesel-equipped models. Thanks to the folks over at the EPA, we now have official estimates for the 2021 GM SUV diesel lineup.
We’ll start with the full-size diesel offerings from Chevrolet. As we previously reported, the 2021 Chevrolet Tahoe in 2WD spec will return 21/28 MPG city/highway, for a total rating of 24 MPG combined. The larger Suburban model fairs slightly worse in 2WD spec, turning out ratings of 21/27 MPG city/highway, and 23 MPG combined. Should you option 4×4, both the 2021 Chevrolet Tahoe and 2021 Chevrolet Suburban return the same figures of 20/26 MPG city/highway and 22 MPG combined. Not bad for these three-row T1 Platform behemoths.

Things get a little more interesting when we look at the GMC Yukon and Yukon XL models. The 2WD Yukon with the Duramax diesel is slightly less efficient than its Chevy sibling, returning ratings of 21/27 city/highway, and 23 MPG combined. However, the larger GMC Yukon XL model is able to match this figure when optioned with 2WD. Like with the Chevy models, both SUVs see a slight dip in fuel economy when 4×4 is equipped, returning 20/26 MPG city/highway and 22 MPG combined.
As of now, we don’t have the full fuel economy ratings for the 2021 Cadillac Escalade lineup. That said, the automaker has confirmed that the LM2 diesel-powered ‘Sclade in 2WD spec will return 21/27 city/highway, and 23 MPG combined. Considering this figure is in line with the offerings from GMC, it is pretty safe to assume that the 4×4 Escalade models will match the rest of the 2021 GM SUV diesel lineup.

The 3.0L Duramax diesel is then the most efficient offering in the 2021 T1 SUV engine lineup. That isn’t a huge surprise, considering how efficient the engine was in the Silverado and Sierra 1500 models. It’s not terribly expensive either, carrying just a $995 premium over the standard 5.3-liter V8 on most trims. GM will even offer a $1,500 credit for buyers who option the diesel on trims that come as standard with the larger 6.2L V8. That money buys quite a lot of diesel fuel.

So a $1500 credit to option out of the 6.2 liter to get the baby diesel. Can I option that in the 2500 or will it just be over taxed/dog
Unfortunately the 3.0L Duramax isn’t available in a 2500 spec. Nor are there 2500 Tahoe and Suburbans for the 2021 model year.