Chevrolet and GMC will start taking orders for the diesel soon, though.
UPDATE: Since publishing this story earlier today, Chevrolet released specs for the 3.0-liter diesel. It makes 277 horsepower (207 kilowatts) and 460 pound-feet (634 Newton-meters).
General Motors will delay offering the 3.0-liter diesel inline six in the 2020 Chevrolet Silverado 1500 and GMC Sierra 1500, according to a memo from GM to dealers that Automotive News obtained. The note indicated that emissions certification was taking longer than the company expected, resulting in the extended wait for the engine to come to market.
Gallery: 2019 Chevrolet Silverado
"Yes, we are shifting the 3.0L Diesel from a late 2019MY to a 2020MY as emissions testing is taking longer than expected," Chevrolet representative Monte Doran told Motor1.com. "However, we did not attribute to a single entity, as the truth is this is a collaborative effort between GM and several government entities. We will make the 2020MY Duramax available for dealers orders soon, and expect to deliver the first trucks to customers soon after emissions testing is complete."
Chevrolet initially announced that the 3.0-liter turbodiesel would be available on the 2019 Silverado "in early 2019" with a 10-speed automatic and stop-start. The company never announced official specs for the powerplant, but GM's Mark Reuss said he was "really confident that we'll have the best performing diesel in the segment."
A leak in 2018 from GM's Canadian dealer website indicated that the engine in the GMC Sierra 1500 would make 282 horsepower (210 kilowatts) and 450 pound-feet (610 Newton-meters) of torque. Judging by other engines available in the pickups, it would have the same output in the Silverado 1500. However, EPA certification might have required GM's engineers to revise the tuning for the road-going version of powerplant to have a different output.
GM's statement also indicated that the 2020 Silverado and Sierra were getting available adaptive cruise control, and the 5.3-liter V8 would get the 10-speed automatic gearbox.
The Silverado is available with quite an array of engines, even without the diesel's availability. The base engine is a 4.3-liter V6 with 285 hp (213 kW) and 305 lb-ft (414 Nm), and the 2.7-liter turbocharged four-cylinder packs 310 hp (231 kW) and 348 lb-ft (472 Nm). The V8 options include a 5.3-liter offering with 355 hp (265 kW) and 383 lb-ft (519 Nm) or a 6.2-liter with 420 hp (313 kW) and 460 lb-ft (624 Nm).
Source: Automotive News
May 21, 2019
To: Dealer Operators, Sales Managers & Inventory Managers
Subject: 2019 Model Year 3.0L Duramax Diesel Engine Cancellation
Statement on Silverado and Sierra 3.0L Duramax timing.
GM is currently working with government officials to complete emissions certification of this great new product. Unfortunately, the process is taking longer than anticipated. Therefore, rather than do an abbreviated production for the 2019 Model Year, GM will launch the 3.0L Duramax as a 2020 Model Year with production starting soon.
The decision to introduce the 3.0L Duramax as a 2020 Model Year will necessitate the return and cancellation of existing 2019 Model Year production. Dealers and customers impacted by this action will be offered a replacement 2020 Model Year vehicle. Notification and timing associated with the replacement order will be provided through a subsequent communication.
What else is new for 2020 Model Year?
We have many significant updates for 2020, including:
New available Adaptive Cruise Control (Silverado and Sierra)
New available 5.3L/10-speed transmission combination (Silverado and Sierra)
Expanded availability of the 6.2L V-8 (Silverado)
Expanded trim offerings and special editions (Sierra Elevation Crew & CarbonPro)
Please accept our apologies for any inconvenience caused by the slight delay in the 3.0L Duramax.