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6.6L Duramax LML





The LML Duramax was released for 2011 model General Motors & Chevrolet HD trucks. The latest version of the 6.6L Duramax, the LML uses 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 & meet future future requirements as well. Not only is the LML the cleaniest Duramax in history; it is also the most powerful, with 397 horsepower & 765 lb-ft of torque.



6.6L Duramax LML Specs


6.6L Duramax LML, 90 degree V8, diesel.

Years Produced:

2011 - current

VIN Code:

8 (8th digit of VIN)


403 cubic inches, 6.6 liters.

Head/Block Material:

Aluminum cylinder heads, cast iron engine block.

Compression Ratio:

16.8 : 1

Firing Order:



4.06 inches.


3.90 inches.


Garrett variable vane (VVT), variable geometry turbocharger (VGT) with air-to-air intercooler.


Direct injection, 30,000 psi Bosch high pressure common rail w/ CP3 injection pump and piezo injectors.


OHV (overhead valve), 4 valves per cylinder.

Oil Capacity:

10 quarts w/ filter.

Peak Horsepower:

397 hp @ 3,000 rpm.

Peak Torque:

765 lb-ft @ 1,600 rpm.


Additional Duramax LML Info

• B20 biodiesel compatible (20% biodiesel, 80% petroleum diesel mixture).
• The Duramax LML has a total of 9 fuel injectors - 1 injector for each of its 8 cylinders, and a 9th injector in the turbocharger downpipe to facilitate the active regeneration process (burning off soot in the DPF).
• Fuel mileage increased by 11% over 2010 models.
• Factory equipped exhaust brake, but without the traditional butterfly valve mounted behind the turbocharger. Instead, the variable vane, variable geometry turbocharger doubles as an exhaust brake.
• GM states: "The engine has been developed to operate for at least 200,000 miles on a rough-duty cycle without the need for a major overhaul."
• The LML is available mated to the Allison 1000 6 speed automatic transmission - no manual transmission is available.
• The Duramax LML is comprosed of 60% newly designed components (components not carried over from a previous model).
• Engine block upgraded for increased strength & engine noise reduction.
• Upgraded oil pump increases flow at low rpm.
• Higher strength pistons and connecting rod pins.
• Upgraded main bearing design.
• Oil circuit changed to increase oil flow/pressure to the turbocharger.
• EGR cooler bypass is introduced to reduce soot build up in the EGR system.
• The LML was GM's answer to Ford's 6.7L Power Stroke. Shortly after launched the new Power Stroke, GM announced the LML, which surpassed Ford in horsepower and torque. In response, Ford issued a free performance upgrade (via PCM reflash) that bumped the 6.7L to 400 horsepower and 800 lb-ft.


LML Duramax Emissions System

• Diesel particulate filter (DPF) nearly eliminates emissions of diesel soot. Active regeneration programming cleans the DPF periodically (estimated regen period every 700 miles, 300 miles less then previous systems, under normal operating conditions) by injecting diesel fuel into the exhaust stream via a "downstream injector", completely burning off soot captured in the DPF.
• Exhaust gas recirculation (EGR) with EGR cooler.
• Selective catalyst reduction (SCR) utilizing diesel exhaust fluid injection (DEF). DEF is a urea based fluid injected into the SCR to further reduce nitrogen oxide emissions. A DEF tank will need to be filled approx. every 5,000 miles (under normal operating conditions). Engine will enter into a limp-mode if DEF tank is empty.
• EGR cooler bypass to help eliminate soot deposits in the EGR cooler/system, which could potentially cause engine problems.


LML Duramax DEF

The LML Duramax is equipped with a SCR system that requires the use of DEF (diesel exhaust fluid). DEF is injected into the exhaust stream where a chemical reaction occurs that reduces NOx emissions. The DEF tank is approximately 5 gallons (18.9 liters). On pickup trucks, the DEF tank fill nozzle is located on the passenger side, under the hood and is sealed by a blue cap. On vans, the DEF tank fill nozzle is located in the fuel fill door, and is also sealed by a blue cap. The DEF system will illuminate a warning indicator in the instrument panel when the DEF fluid levels range is estimated to be 1,000 miles. Subsequent warnings will follow.

• If the DEF fluid level is depleted, an "EXHAUST FLUID EMPTY" notification will be displayed on the instrument panel. Upon restart, the truck will be speed limited to 55 mph. If the tank remains empty, speed will be limited to 4 mph after the second refueling. Performance may also suffer when the truck enters this mode.

• If the DEF fluid quality is detected to be low, an "EXHAUST FLUID QUALITY POOR" notification will be displayed on the instrument panel. After 200 miles of driving with poor quality DEF, the truck will be speed limited to 55 mph. If the system continues to detect low quality DEF, speed will be limited to 4 mph upon the next refueling.

• If the DEF system detects that it requires service, a "SERVICE EXHAUST FLUID SYSTEM" notification will be displayed on the instrument panel. Failure to have the system serviced within 200 miles will result in speed limited to 55 mph upon the next startup, and 4 mph on the next refuel.