Late August, GM Authority reported that production of the 3.0L LM2 turbo-diesel Duramax engine was temporarily halted due to a supplier issue. Now, GMA has learned that production of the engine will be idled for the remainder of the 2021 calendar year.
The 3.0L I6 LM2 Duramax diesel engine is assembled at the GM Flint Engine Plant in Flint, Michigan. It is offered as an option in GM’s full-size half-ton pickup trucks and full-size SUVs, including the Chevy Silverado 1500, GMC Sierra 1500, Chevy Tahoe, Chevy Suburban, GMC Yukon, and Cadillac Escalade.
The LM2 engine features a straight six configuration with a DOHC valvetrain, 84mm bore, and 90mm stroke, with a 15.0:1 compression ratio. The block and heads are made of aluminum, with a forged steel crankshaft and forged rods. The pistons are made from hypereutectic cast aluminum alloy, while the cylinder liners are made from iron.
The fueling system uses a common rail with direct fuel injection. Induction air is chilled using a liquid-to-air intercooler.
Output of the LM2 is rated at 277 horsepower at 3,750 rpm and 460 pound-feet of torque at 1,500 rpm in all of the aforementioned vehicles. For the 2019, 2020 and 2021 model years, the LM2 is mated to GM’s 10-speed automatic transmission, no matter the vehicle application.
While the healthy amount of low-end torque make it a great option for towing duties, the turbocharged 3.0L I6 LM2 Duramax diesel is also quite fuel efficient. For example, when equipped in the 2021 Chevy Suburban with rear-wheel drive, the LM2 delivers 21 mpg in the city, 27 mpg on the highway, and 23 mpg combined, with an annual estimated fuel cost of $1,650. By comparison, the 5.3L V8 L84 gasoline engine, which is the base engine in the 2021 Suburban, is rated at a much less substantial 16 mph in the city, 20 mph on the highway, and 18 mph combined.