Duramax Deferral: Emissions Delay Punts Straight-six GM Diesel to 2020 Model Year

General Motors’ new Flint-built, light-duty 3.0-liter inline-six turbo-diesel won’t be a late-year addition to the company’s full-size pickup lineup, after all.

Apparently, the engine’s emissions certification process was not the speedy affair GM had hoped for. Customers will now have to wait for the 2020 model year before getting their hands on the 460 lb-ft oil burner.

The news comes by way of Automotive News, which got its hands on a memo sent to dealers Tuesday. As a result of a “slight delay” in the Environmental Protection Agency’s emissions certification process, dealers must now cancel and resubmit their orders, the memo said.

Production of diesel 2020 Chevrolet Silverado 1500 and GMC Sierra 1500 models should begin “soon,” the automaker said.

Since Volkswagen’s diesel emissions scandal in 2015, the EPA has taken a more rigorous approach to vetting diesel powerplants, leading to delays in certification. Fiat Chrysler’s EcoDiesel affair certainly didn’t help the EPA’s paranoia, either. The same situation is occurring overseas, where certain German product launches ran into unexpected delays as a result of the slower process.

With its new 3.0L Duramax, GM hopes to best a Detroit rival in light-duty diesel performance. Ford launched its 3.0L Power Stroke diesel for the 2018 model year and, while the Duramax powerplant bests it in terms of output (277 hp and 460 lb-ft, versus Ford’s 250 hp and 440 lb-ft), the GM engine’s fuel economy and towing figures remain unknown.

The automaker claims drivers will see 95 percent torque output at 1,250 rpm, with peak torque coming online at 1,500 rpm and staying until 3,000 rpm. Like the Ford, the only transmission available with the new GM diesel is a 10-speed automatic.

By adding an available diesel across multiple trims, GM hopes to boost the average transaction price of its new-generation pickups even further. Last quarter, the company said full-size ATPs were $8,040 higher than than of the old-gen pickup in the same quarter a year earlier. Helping the figure, of course, was the fact that full production of Silverado and Sierra regular and double cabs didn’t start until March.

[Image: General Motors]