GM Duramax Diesel
The Duramax diesel is a result of a joint venture between GM and Isuzu which
resulted in the formation of " DMAX Ltd". the Duramax engine was the first
high-pressure common-rail, direct-injection diesel in the U.S. Diesel market.
The first engine was produced in Moraine, Ohio, on July 17,
Common Problems with the
- GM Duramax 6.6L2001 - 2004 LB7
- First Generation 2000 Duramax diesel engine with 300 hp
and 520 lb-ft torque in ’01 ¾- and 1-ton trucks. The 6.6L V-8
turbodiesel engine featured aluminum heads with 32 valves on a cast-iron
block, high-pressure, common-rail, direct fuel injection, a
fixed-geometry turbo, injectors mounted under the valve covers, and a
passive catalytic converter.
- GM Duramax 6.6L 2004.5 - 2005 LLY
- The LLY Duramax was introduced mid-model year with 310 hp and 605
lb-ft of torque, featuring an improved valve design to make the
injectors more accessible for repair. A variable-geometry turbo was
added, which used movable vanes in the turbine housing. The vanes
dynamically change the volume of air on the exhaust side of the turbo,
improving low-end response while retaining a large turbine volume during
high engine speeds. Emissions were addressed with the addition of an
exhaust gas recirculation system, which routed a portion of the exhaust
into a cooler before sending it back through the engine for a secondary
- GM Duramax 6.6L 2006 - 2007 LLY/LBZ
- LBZ Duramax was introduced for the ’06 model year and featured
a number of improvements that enabled the engine to produce up to 360 hp
and 650 lb-ft of torque. The LBZ became a favorite of tuners, thanks to
a stronger block design, larger connecting rods, new piston design, and
heads that could handle more pressure. Higher fuel pressure levels,
larger fuel rails, six-hole injectors, an improved variable-geometry
turbo, and a larger EGR cooler setup were also added. An advanced,
32-bit engine computer helped improve power, efficiency, and emissions.
Although the engine was saddled with EGR, the LBZ was the last Duramax
offered without a fuel-economy-robbing diesel particulate filter (DPF).
This meant the exhaust system could be altered while keeping the truck
street-legal. 2006 was also the year GM introduced the six-speed Allison
transmission to the Duramax powertrain
- GM Duramax 6.6L 2007.5 - 2000 LMM
- The LMM Duramax engine was introduced with 365 hp and 660 lb-ft of
torque. Along with the large EGR and passive catalytic converter, the
LMM was the first Duramax to be fitted with a DPF. The DPF was an active
catalytic converter and filter that heralded the new age of active
regeneration. This reduced fuel mileage due to the need for extra fuel
to be burned when the filter was full of soot. It also dramatically
reduced the amount of particulate pollution produced by the engines so
they could meet the stringent new emissions standards being introduced
by the Federal Government. Despite this fact, engineers figured out a
way to be cleaner while making the LMM the most powerful Duramax to
- GM Duramax 6.6L 2011 - 2015 LML
- The current version LML engine is a massive 397 hp and 765
lb-ft of torque and meets the most stringent emissions laws to date.
Once again, engineers were able to squeeze out another 105 lb-ft of
torque while making the engine run dramatically cleaner than the
previous generation. This was accomplished with the use of multiple new
features, including super-fast-reacting piezo-controlled injectors
(which are capable of multiple injections per cycle for optimal
combustion), a ninth injector mounted downstream from the turbo to help
DPF regeneration, a new EGR system with a cooler bypass, and a new
selective catalytic reduction (SCR) system with urea injection.
new engine design also came with a B20 rating, allowing owners to use
fuel blends with up to 20 percent biodiesel content without voiding
their warranty or risking damage to the engine or fuel system.
LML also added a “smart” exhaust brake built into the turbo, which is
activated by the driver using a button on the center console. This
exhaust brake has different modes of operation when the truck is in
Tow/Haul mode or when the cruise control is activated.
The next Duramax from GM may be a 2016/2017 model with improvements
to provide more horsepower and more torque. The turbo-diesel engine slated for
the Chevrolet Silverado 2500/3500 and GMC Sierra 2500/3500 models will use the
same 6.6-liter Duramax block but offer a smarter injector system and a more
sophisticated electronic control module.
Preliminary reports indicate 440 hp
and 850 pounds-feet of torque. GM has made no official announcement about the
The ASE certified diesel technicians at R&M diesel will
stay on top of all the new changes.