There probably aren't many people who remember the last time Cadillac offered a diesel engine option for its coupe and sedans. Yes, for a brief period from 1978 to 1985 buyers could look forward to—if that's the right perspective—a factory-installed oil burner borrowed from Oldsmobile in their Cadillac luxobarges. The 5.7-liter LF9 V-8 diesel could be had in the Eldorado, Seville, de Ville, and Fleetwood Brougham, and it was intended to pick off high-end car buyers who'd otherwise be flocking to Mercedes-Benz's sturdy and luxurious diesel vehicles at the time. Today, Cadillac is giving diesel another try in its all-new 2021 Escalade SUV, and for similar reasons.

We'll concede the idea that Caddy selling a diesel might be as difficult to fathom for Millennial Cadillac buyers who weren't around nearly 40 years ago as it is for those older customers who were and suffered through that Malaise-era disaster. For the first time in its 21-year lineage, the Escalade is being offered with diesel power. In this case, it is a 3.0-liter Duramax turbodiesel inline-six. As the same engine comes in the next-generation Chevrolet Tahoe and Suburban (and their GMC siblings), it is paired with GM's 10L80 10-speed automatic transmission.

Diesel by Duramax

This new LM2 engine was designed from the ground up in-house at GM. The block is constructed of cast aluminum, an oddity in a world where diesel engine blocks are commonly produced of the ultra-strong compacted graphite iron (CGI). Using aluminum nets a 25-percent weight savings over an iron block, and to aid longevity, GM added iron cylinder liners to cope with the 15:1 compression ratio.

A single set of dual overhead camshafts (it's an inline-six, 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 one 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.

The LM2 inline-six's 277 horsepower and 460 lb-ft of torque more than double up the figures of Cadillac's original diesel from way back when. (That V-8 produced a downright pathetic, by modern standards, 125 ponies and 224 lb-ft of torque.) It also surely will deliver smoothness and low noise, vibration, and harshness (NVH)—the old GM diesel, by contrast, delivered seemingly maximum levels of those things.

How Much Will It Cost, and How Efficient Is It?

Even though pricing for the Escalade's optional 3.0-liter Duramax diesel engine is forthcoming, we figure it won't command much more than the $2,500 Chevrolet and GMC charge for it in the Silverado and Sierra pickup trucks. Fuel economy is the same story—while the pickups are EPA-rated for up to 33 mpg highway with the oil burner, final Escalade figures have yet to be released. Expect to see mpg numbers in the mid- to high 20s (at least) for the Cadillac.

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.

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