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Diesel Returns to Cadillac!

Luxury Automaker Adds GM’s 3.0L Duramax Diesel/Ten-Speed Transmission to 2021 Escalade’s Powertrain Options.

KJ JonesAuthorSteven PhamPhotography

There probably aren't many people who remember the last time Cadillac included a diesel engine as an optional powerplant for its coupe and sedans.

Yes, there really was a brief period—1978 to 1985—when a factory-installed oil burner (Oldsmobile's 5.7L LF9 V-8) could be had in Caddy-badged luxobarges such as Eldorado, Seville, de Ville, and Fleetwood Brougham. The diesel was offered in an effort by General Motors to earn a piece of the high-end-car-buyer pie that Mercedes-Benz was enjoying through sale of its diesel vehicles.

A New Generation of Diesel

Hard to believe? We'll concede it might be difficult to fathom, especially for Millennial Cadillac buyers and younger diesel enthusiasts who weren't around nearly 40 years ago. But, it's quite true, and that history is now repeating itself in the 2021 Cadillac Escalade; produced in Arlington, Texas, and arriving at U.S. dealerships late this summer.

Yes, for the first time in its 21-year lineage, Escalade is being offered with a 3.0L Duramax LM2 I-6 turbodiesel engine and 10L80 ten-speed automatic transmission; the same drivetrain package that's available for Chevrolet's next-generation Tahoe and Suburban, and GMC's Yukon and Yukon XL, as well as the 1500 Series pickup trucks that each brand rolled out in late 2019.

The Duramax I-6

This new engine was designed from the ground up by the engineers at GM. The I-6 block is constructed of cast aluminum, which is an oddity in a world where diesel engine blocks are commonly produced of the ultra-strong compacted graphite iron (CGI). The use of aluminum produces a 25-percent weight savings over an iron block. To aid longevity, GM added iron cylinder liners to cope with the 15:1 compression ratio and forces created from combustion.

A single set of dual overhead camshafts (it's an I-6, remember) operate each of the engine's 24 valves, which feature maintenance-free finger followers and hydraulic lash adjusters. Owing to the engine's length, the camshaft drivetrain is on the back of the engine. A chain drive on the crankshaft operates the high-pressure direct-injection fuel pump, and a chain on the fuel pump runs to the intake and exhaust cams. A smaller belt on the crankshaft runs the variable-flow oil pump.

Airflow is provided by way of a single, variable-geometry turbocharger, and a variable intake manifold provides two paths into each cylinder—a short and a long one. Electronic flaps select which air path to use, improving engine response particularly at low rpm. And fuel is provided by way of high-pressure common-rail direct injection, capable of multiple injection events per cycle and pressures up to 36,250 psi.

Compression-Ignition Anticipation

While the 3.0L I-6 engine's 277 hp/460 lb-ft are more than double the OG's 125hp/224 lb-ft performance output (which actually seems downright anemic today), diesel reenters the Cadillac picture with even greater smoothness and much lower NVH characteristics than it had during its first run.

Pricing is yet to be announced, however in the Silverado and Sierra pickups, the 3.0L Duramax diesel commands a $2,500 premium over the 6.2L gasoline V-8. We would expect a similar figure for the Escalade as well. Same can be said for fuel economy, which also hasn't been released. The pickups rate up to 33 mpg highway with the oil burner, so we will be happy to see mid to high 20s for the heavier SUV.

With Escalade being roughly 1,000 pounds heavier than GM's like-powered pickups (based on a crew-cab pickup versus a 2021 Suburban), it will be interesting to see whether there is a significant performance difference from a driving perspective when the time comes, and ultimately how real-world fuel economy varies between the trucks and high-end SUV.