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GM 6.6 Liter L5P V-8 Duramax Turbo Diesel Engine
The GM L5P Duramax is a turbo-diesel engine produced by General Motors for use in full-size heavy-duty (HD) pickup trucks. Displacing 6.6 liters in a V-8 configuration, the L5P is part of a new generation of Duramax engines. It succeeds the 6.6L Duramax V-8 LML engine.
| Displacement: | 6.6L / 403 cu. in. |
| Aspiration: | Natural |
| Vehicles: | Chevrolet Silverado HD, GMC Sierra HD |
| Introduced: | 2017 model year |
| Discontinued: | – |
| Predecessor: | LML Duramax V8 |
| Successor: | – |
| Assembly: | Moraine, Ohio, USA |
Overview
When the GM L5P engine made its debut in the 2017 Chevrolet Silverado HD and 2017 GMC Sierra HD, it produced an SAE-certified 910 pound-feet of torque (1,234 Nm) and 445 horsepower (332 kW). Output remained the same for the next-generation 2020 Chevrolet Silverado HD and 2020 GMC Sierra HD models. It received an increase in power and torque for the 2024 model year Silverado HD and Sierra HD.
Notably, the Duramax 6.6L represents a next-generation redesign that features an all-new, stronger cylinder block and rotating assembly, as well as a new, GM-developed control system. The engine’s production of low-rpm torque — a Duramax Diesel signature — hasn’t changed: the L5P offers 90 percent of peak torque at a low 1,550 rpm and sustains it through 2,850 rpm, an attribute that contributes to the strong, confident pulling power at low speeds of the vehicles in which it powers.
The new L5P also features a new camshaft profile and improved cylinder head design; a new electronically controlled, variable-vane turbocharger allows the engine to produce more power with lower exhaust emissions. The engine’s advanced variable-vane mechanism allows greater exhaust temperature capability, enabling the engine to achieve higher power at lower cylinder pressure.
Additionally, a new, patent-pending vehicle air intake system with functional hood scoop drives cool, dry air into the engine for sustained performance and cooler engine temperatures during difficult conditions, such as trailering (towing) on steep grades.
Cooler air helps the engine run better under load, especially in conditions where engine and transmission temperatures can rise quickly. This enables the Duramax to maintain more power and vehicle speed when trailering in the toughest conditions.
The upgrades provide increases in real-world towing experience for the heart of the Heavy Duty pickup truck market — with 89 percent of all HD customers purchasing trucks rated less than 25,000 pounds of towing capacity. For these customers, the new Duramax diesel in the 2017 Chevrolet Silverado HD and 2017 GMC Sierra HD offers:
- Unladen, 0-60 mph acceleration in as quick as 7.1 seconds in the GM 2500HD Crew Cab 4WD models, seven-tenths of a second quicker than the last-generation model
- Towing 10,000 pounds, acceleration from 50 to 70 mph in 10.6 seconds in the 2500HD regular cab 4WD models, 1.5 seconds quicker than the last-generation model
- When towing 23,000 pounds in 110-degree Fahrenheit ambient temperature, the Silverado and Sierra 3500HD Crew Cab 2WD with DRW climbs the Davis Dam grade 40 seconds quicker than the last-generation model
“The new Duramax delivers impressive output, but what customers will appreciate the most is an improved driving experience,” said Eric Stanczak, Silverado chief engineer. “It delivers quicker acceleration in virtually all measures, more confidence when trailering up a steep grade, better engine braking on descent and more refined noise levels cruising on the highway.”
Specs
| Type | 6.6L V-8 Turbo-Diesel |
| GM RPO Code | L5P |
| Displacement | 403 ci |
| Compression Ratio | 16.0:1 |
| Valve Configuration | Overhead |
| Valves Per Cylinder | 4 |
| Assembly Site | Moraine, Ohio, USA |
| Valve Lifters | Mechanical roller |
| Firing Order | 1 – 2 – 7 – 8 – 4 – 5 – 6 – 3 |
| Bore x Stroke | 103 x 99 mm |
| Fuel System | Direct injection with high-pressure common rail |
| Fuel Type | Ultra-low-sulfur diesel and B20 biodiesel |
| Maximum Powered Speed | 3450 rpm |
| Maximum Braking Speed | 4800 rpm |
| Emissions Controls | Cooled Exhaust Gas Recirculation (EGR), Selective Catalytic Reduction (SCR), Diesel Particulate Filter (DPF), intake throttle |
| Block | Cast iron |
| Cylinder Head | Cast aluminum |
| Intake Manifold | Cast aluminum |
| Exhaust Manifold | Cast nodular iron with steel pipe extension |
| Main Bearing Caps | Cast nodular iron |
| Crankshaft | Forged steel |
| Camshaft | Steel |
| Connecting Rods | PM iron |
| Engine Oil Capacity | 10 qt./9.5L |
Vehicle Applications
| Model Year | Vehicle | Transmission | Power (hp / kW) @ RPM | Torque (lb-ft / Nm) @ RPM |
|---|---|---|---|---|
| 2017 – 2023 | Chevrolet Silverado HD | Allison Transmission MGM | 445 / 322 @ 2800 | 910 / 1234 @ 1600 |
| 2017 – 2023 | GMC Sierra HD | Allison Transmission MGM | 445 / 322 @ 2800 | 910 / 1234 @ 1600 |
| 2024 – Present | Chevrolet Silverado HD | Allison Transmission MGM | 470 / 350.5 @ 2800 | 975 / 1322 @ 1600 |
| 2024 – Present | GMC Sierra HD | Allison Transmission MGM | 470 / 350.5 @ 2800 | 975 / 1322 @ 1600 |
The L5P has a derivative called L5D that’s used in the 2019 Chevrolet Medium Duty Trucks – the 2019 Silverado 4500HD, Silverado 5500HD and Silverado 6500HD.
Manufacturing
The 6.6L Duramax L5P engine is manufactured at the GM Duramax plant in Moraine, Ohio, USA.
News
Follow our Duramax L5P news coverage.
Sponsored Links
- GM 6.6 Liter V-8 L5P Duramax Turbo Diesel Engine Power Ratings
