Leaks are a common issue for automakers, particularly when they depend on a network of independent dealers to maintain confidentiality. Recently, details regarding the performance specifications of the new diesel engine for the GMC Sierra and Chevrolet Silverado have surfaced online.
According to TFLtruck, information allegedly sourced from GM Canada’s dealer site indicates that the inline-six Duramax diesel engine produces 282 horsepower and 450 pound-feet of torque. These documents also suggest the engine will achieve 28 miles per gallon on the highway.
If accurate, these power and torque figures would surpass those of Ford’s half-ton Power Stroke diesel, which is rated at 250 horsepower and 440 lb-ft of torque. This isn’t unexpected, as automotive manufacturers often strive to outdo each other, and GM would likely want to showcase its truck as having the best horsepower and torque in its class once it is released.
The documents shared with TFLtruck also reveal that the GMC Sierra, when equipped with the diesel engine, can tow up to 7,800 pounds.
How reliable are these figures? The horsepower and torque seem plausible as they would indeed represent top-of-the-line performance. Minor software adjustments could easily allow manufacturers to enhance their numbers to stay competitive.
However, the fuel efficiency rating may be a letdown, at least on paper. For instance, a rear-wheel-drive Ford F-150 powered by a Power Stroke engine is rated at 30 miles per gallon on the highway, making it unlikely that GM’s truck would only manage 28 or 29 mpg under similar conditions.
The most concerning figure appears to be the towing capacity. Currently, the GMC Canyon or Chevrolet Colorado midsize diesel trucks can tow up to 7,700 pounds in a two-wheel-drive setup (7,600 pounds in four-wheel drive). The increase in towing capacity of just 100 pounds for a larger and heavier-duty truck seems improbable. In contrast, the F-150 has a maximum towing capacity of 11,400 pounds with its diesel configuration.
The GM diesel engine is expected to be released next year, and official specifications will be provided closer to its launch. For now, we can only speculate on these initial figures.
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