The LML Duramax was released for 2011 model General Motors & Chevrolet HD trucks.The latest version of the 6.6L Duramax requires advanced emissions equipment, including the use of diesel exhaust fluid injection, to reduce nitrogen oxide emission levels by 63 percent over LMM powered trucks. This allows the LML to exceed currently mandated federal emissions requirements and potentially meet future requirements as well. The LML was replaced for the 2017 model year by the next generation Duramax L5P.


The Duramax LML introduced the “9th injector” system in order to supply fuel to the DPF during regeneration. This is opposed to the previous generation’s (LML) late/post injection technique. The result eliminated cylinder washing concerns and permitted the use of up to B20 biodiesel. The implementation of the SCR system, which requires a constant supply of diesel exhaust fluid (DEF), was met with heavy scrutiny. However, this technology actually allows for an advantageous engine calibration to be executed, reducing the duty cycle of DPF regenerations and providing significant improvements in fuel economy. DEF is not particularly costly and owners incur noticeable fuel savings even while factoring in the cost of exhaust fluid. GM’s official statement is that fuel mileage increased 11% over the previous generation LMM engine.

The LML is said to have been engineered using 60% newly designed components not carried over from a previous generation Duramax. This includes an upgraded engine block casting, oil pump, high strength pistons and connecting rods, main bearing design, and re-routed oil passage circuit. Rated at 397 horsepower and 765 lb-ft of torque, the engine is significantly more powerful than any prior Duramax. General Motors blindsided Ford with the release of these figures, which were revealed shortly after Ford’s 390 hp/735 lb-ft 6.7L Power Stroke became available. A concerned Ford quickly acted to increase the Power Stroke’s available horsepower and torque rating, issuing a free performance upgrade to owners which would re-calibrate the engine to the tune of 400 horsepower and 800 lb-ft.


Engine: 6.6L Duramax LML, 90 degree V8 diesel
Assembly Location: DMAX assembly plant in Moraine, Ohio
Years Produced: 2011 – 2016 model years
VIN Code: 8 (8th digit of VIN)
Displacement: 403 cubic inches, 6.6 liters
Assembly Site: DMAX engine plant, Moraine, Ohio
Head/Block Material: Aluminum cylinder heads, cast iron engine block
Compression Ratio: 16.0 : 1
Minimum Cylinder Pressure: 300 psi (minimum compression test pressure)
Firing Order: 1-2-7-8-4-5-6-3

Duramax diesel cylinder numbers

Bore: 4.055″ (103 mm)
Stroke: 3.897″ (99 mm)
Aspiration: Turbocharged and intercooled – Garrett GT3788VA variable vane turbocharger (VVT), air-to-air intercooler
Injection: Direct injection, 2000 bar (~30,000 psi) Bosch high pressure common rail w/ CP4 injection pump and Piezo injectors
Valvetrain: OHV (overhead valve), 4 valves per cylinder, mechanical roller lifters
Oil Capacity: 10 quarts w/ filter (9.5 liters)
Fuel Compatibility: Ultra low sulfur diesel (ULSD) or max B20 biodiesel blend
Idle Speed: ~ 680 rpm
Max Shift RPM: 3,000 rpm
Peak Horsepower: 397 hp @ 3,000 rpm
Peak Torque: 765 lb-ft @ 1,600 rpm
Engine Dimensions: Length Width Height
Approx 30″ Approx 30″ Approx 32″