6.6 Duramax Specs
The 6.6 Duramax diesel engine is a turbocharged V8 with a displacement of 6.6 liters, designed for heavy-duty performance. When reviewing 6.6 Duramax specs, you’ll find it features a cast iron block, aluminum cylinder heads, and high-pressure common-rail direct fuel injection, depending on the generation. Horsepower ranges from 300 hp in the early LB7 model to over 470 hp in the L5P version. Torque output has grown significantly as well, starting at 520 lb-ft and reaching up to 975 lb-ft in the latest models.
The engine has a bore of 4.05 inches and a stroke of 3.89 inches. It uses a variable geometry turbocharger in most later versions and comes paired with either the Allison transmission or GM’s 10-speed automatic. With strong towing capabilities and advanced emissions systems like EGR, DPF, and SCR, the 6.6 Duramax delivers both power and efficiency for demanding tasks.
6.6 Duramax Specs Key Changes by Model Year
6.6 Duramax LB7 2001-2004
Horsepower/Torque: 300 hp / 520 lb-ft
- First-generation 6.6L Duramax engine with aluminum alloy cylinder heads
- Equipped with Bosch high-pressure common-rail fuel injection system for enhanced efficiency and performance
6.6 Duramax LLY 2004.5-2005
Horsepower/Torque: 310 hp / 605 lb-ft
- Introduced Garrett variable-geometry turbocharger (VGT) for improved performance and responsiveness
- Changed valve cover design to allow injector servicing without removing the entire valve cover
6.6 Duramax LBZ 2005-2007
Horsepower/Torque: 360 hp / 650 lb-ft
- Strengthened engine components to handle increased power output
6.6 Duramax LMM 2007-2010
Horsepower/Torque: 365 hp / 660 lb-ft
- Paired with the Allison 1000 six-speed automatic transmission for smoother shifting and improved power delivery
- Integrated diesel particulate filter (DPF), oxidizing catalyst, cooled EGR, and closed crankcase ventilation to reduce emissions
- Upgraded cooling system for better temperature control and engine performance
6.6 Duramax LGH 2010-2011
Horsepower/Torque: 335 hp / 685 lb-ft
- A de-rated version of the LML, designed primarily for chassis cab and commercial applications
- Equipped with a smaller Garrett variable-geometry turbocharger for optimized low-end performance
- Included full emissions suite: SCR, DPF, DEF, and cooled EGR for compliance with tighter regulations
6.6 Duramax LML 2011-2016
Horsepower/Torque: 397 hp / 765 lb-ft
- Implemented SCR with DEF, DPF, and cooled EGR to meet strict emissions standards
- Upgraded fuel system with Bosch CP4.2 pump and piezoelectric injectors for improved performance
6.6 Duramax L5P 2017-2019
Horsepower/Torque: 445 hp / 910 lb-ft
- All-new engine design with stronger block and heads
- Advanced turbocharging system with BorgWarner VGT
- Enhanced fuel system featuring Denso HP4 pump and solenoid injectors
6.6 Duramax L5P 2020-2023
Horsepower/Torque: 445 hp / 910 lb-ft
- Continued improvements in towing capacity and durability
6.6 Duramax L5P 2024+
Horsepower/Torque: 470 hp / 975 lb-ft
- Increased power output for enhanced performance
- Paired with the 10L1000 10-speed automatic transmission for improved efficiency
Aftermarket Gasket Solutions for 6.6 Duramax Engines
For businesses servicing 6.6 Duramax diesel engine gaskets, having access to dependable, high-performance sealing components is essential. Whether it’s a 6.6 Duramax turbo, injector, intake manifold gasket, or EGR valve gasket replacement, the right products help ensure proper sealing under extreme pressure and temperature.
MJ Gasket offers application-specific solutions across all Duramax generations—from LB7 to the latest L5P—helping engine rebuilders and parts distributors maintain performance, reduce failure rates, and support efficient turnaround times in commercial engine maintenance.
6.6 Duramax Turbo Gasket
Does the 6.6 duramax have a turbo?
Yes, the 6.6 Duramax turbo is a standard feature across all generations of the 6.6L Duramax diesel engine.
From the original LB7 to the latest L5P models, every version includes a turbocharger to deliver the power, torque, and efficiency required for heavy-duty performance. The newest L5P systems are even more advanced, offering greater output and responsiveness.
Because the 6.6 Duramax turbo plays such a critical role, durable turbo gaskets are essential to maintain a secure seal under extreme heat and boost pressure.
For the 6.6 Duramax LB7 to LML turbo systems (2001–2016), MJ Gasket supplies turbo gaskets such as 97188685, 97192618, and 97192619, each built to withstand the thermal demands and boost pressure across fixed and variable geometry turbos. For efficient turbo servicing, the MJ-LB7TRBO1 gasket kit is also available as a complete solution.
For the 6.6 Duramax L5P turbo models (2017–2024+), we offer updated gaskets including 12688018 and 12688019 for turbocharger connections. Turbo pedestal gaskets include 12677294 for 2017–2023 models and 12700564 for 2024 and newer applications. MJ also offers complete turbo gasket kits for the 6.6 Duramax L5P to support various service and replacement needs.
6.6 Duramax Injector Seal
How many injectors does a 6.6 duramax have?
A 6.6 Duramax engine has eight fuel injectors—one for each cylinder in its V8 design. Each 6.6 Duramax injector plays a key role in delivering fuel precisely for efficient combustion. To keep the system sealed and prevent fuel leaks or performance issues, it’s important to replace the injector seals whenever the injectors are serviced.
Injector seal kits are available for 6.6 Duramax injectors, supporting proper sealing and fuel system reliability. Banjo seals are also included for use on fuel feed pipes, fuel return lines, and fuel pressure relief valves—key areas where maintaining a tight seal is essential for engine performance.
6.6 Duramax EGR Valve and Intake Gasket
The EGR valve on the 6.6 Duramax routes exhaust gases back through the intake to reduce emissions. Reliable EGR valve and intake gaskets are essential to prevent leaks, ensure proper gas flow, and maintain the engine’s performance and emission control efficiency.
6.6 Duramax Valve Cover Gasket
The LB7 6.6 Duramax features a distinct valve cover design where the injector wiring passes directly through the cover. Over time, this often leads to fuel and oil leaks around the connectors and grommets. To address these issues, GM redesigned the valve cover in later models, moving the injector wiring outside the cover to improve sealing and reliability.
For the LB7, servicing the valve cover typically involves replacing the valve cover gasket 97188896, lower valve cover grommets 97213862, and fuel injector nozzle seals 97225457. These parts are often grouped into a complete kit to ensure proper sealing and reduce the risk of future leaks.
Starting with the LLY and continuing through later models, GM introduced a two-piece valve cover with separate upper and lower gaskets, simplifying maintenance and reducing leak points.
With the L5P, GM made another update by switching to a one-piece steel valve cover gasket, offering a more secure and consistent seal under higher operating pressures and temperatures.
If you’re interested in any of these items, feel free to click and submit a quote request—our team will follow up with you via email shortly.
Our 6.6 Duramax gasket offerings go beyond what’s shown here, as we continue to expand our product range. If you’re looking for additional parts, simply send us the GMC part numbers, and we’ll get back to you as soon as possible.
