3.0L Duramax

High-tech Diesel Boasts Some Common Wisdom

- Brett T. Evans

General Motors will soon begin to market a 3.0L Duramax I-6 turbodiesel in its light-duty pickup offerings, the Chevrolet Silverado 1500 and the GMC Sierra 1500. And although we were a bit disappointed to learn the engine would be delayed until the 2020 model year, for fans of oil-burning powertrains, it might be worth the wait.

Helping ease the sting of the delay is the relative low cost of the Duramax I-6. In the 2020 Silverado 1500, the diesel will demand the same premium as the 6.2L V-8, $2,495 more than the 5.3L V-8, and $3,890 more than the 2.7L turbocharged I-4. For 2020, the Duramax will be offered in LT, RST, LTZ, and High Country trims. The Silverado 1500 Duramax should slot in around $45,000 or so at the low end, and it will be an efficient thing as well: 23/33 mpg for the 4x2 and 23/29 for the 4x4.

Duramax I-6 Goodness

General Motors is rightly proud of the engine’s torque curve, which boasts a peak 460 lb-ft between 1,500 and 3,000 rpm, with more than 430 lb-ft available at 1,250 rpm—as well as 277 hp at 3,750 rpm. A variable-geometry turbocharger helps enable lag-free torque delivery, at least theoretically, with a maximum of 43.5 psi of boost. A water-to-air intercooler helps reduce charge-air temperatures, improving both performance and engine durability.

And while Ford and Ram both use a DOHC 3.0L V-6 for their light-duty diesel pickups, GM says the Duramax I-6 is a better choice for a truck thanks to the inline engine’s inherent smoothness. An I-6 offers balanced primary and secondary rotational forces, precluding the need for a balance shaft. No balance shaft and the DOHC I-6’s need for only two camshafts lead to reduced friction, improved efficiency, and better noise/vibration/ harshness isolation.

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