6.6L Duramax LML

Time:2017-12-16 18:30Turbochargers information Click:

lm 6.6 duramax lml duramax lml

Duramax Receives SCR System, DEF

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.

6.6L Duramax LML Specs


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)


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:


Duramax diesel cylinder numbers


4.055" (103 mm)


3.897" (99 mm)


Turbocharged & intercooled - Garrett variable vane (VVT), variable geometry turbocharger (VGT) with air-to-air intercooler


Direct injection, 2000 bar (~30,000 psi) Bosch high pressure common rail w/ CP4 injection pump and Piezo injectors


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:




Approx 30"

Approx 30"

Approx 32"

Duramax LML Horsepower & Torque Graph

6.6L Duramax LML horsepower and torque graph

6.6L Duramax LML horsepower & torque (Silverado, Sierra)
Source: GM Powertrain Division,

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.

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