GM Duramax 3.0-Liter I-6 LM2 Turbo Diesel Engine

The GM Duramax 3.0L I-6 LM2 is a turbo-diesel engine produced by General Motors for use in various vehicles, primarily full-size half-ton pickup trucks and full-size SUVs. Colloquially known as “baby Duramax”, the engine is an all-new design from the ground up.

In May 2018, GM Authority was first to report that the engine has been assigned GM RPO code LM2.

Overview

The cylinder block of the GM Duramax 3.0-liter LM2 is made of a cast aluminum alloy that provides the strength required to support the high combustion pressures that occur within a diesel engine, while also offering an approximately 25 percent mass savings over a comparable cast iron engine block. Iron cylinder liners are used within the aluminum block to insure truck durability.

Additional engine features include:

• A high 15.0:1 compression ratio
• Seven nodular iron main bearing caps that help ensure the block’s strength under those high combustion pressures
  • Enables accurate location of the rotating assembly
• A deep-skirt block design, where the block casting extends below the crankshaft centerline
  • Contributes to the engine’s stiffness and refinement
• Stiffness-enhancing aluminum lower crankcase extension attached to the main bearing caps
• Forged steel crankshaft
• Forged steel connecting rods and hypereutectic aluminum pistons
  • Alloys in the respective castings for the rods and pistons make them lightweight and durable
  • Silicon is blended with the aluminum for heat resistance and tolerance within the piston cylinders, which enhances performance and makes the engine quiet
• A thick piston crown, which is the top of the piston
• Reinforced top ring add strength to support tremendous cylinder pressures
• Capable of exhaust brake, which is available in tow-haul mode, can provide additional driver confidence when towing, especially when going downhill
  • When paired with 10-speed automatic transmission

Compared to a DOHC V-6, the inline-six architecture offers greater efficiency from the reduced friction of operating only two camshafts and their associated valvetrain components. The I6 configuration offers the perfect balance of primary and secondary forces, without the need for balancing shafts.

“In addition to reduced friction, the architecture enables smooth operation,” Menarini said. “The new Duramax 3.0L elevates the 2019 Silverado with one of the most refined and efficient diesel engines in the segment.”

Along with supporting elements such as a tuned air induction system and other noise-attenuating elements, the 3.0L Duramax delivers exceptional quietness and smoothness at all engine speeds.

Specs

Vehicle Applications

Pictures