Is the 2024 6.6 Duramax a good engine?
Yes. The 2024 Duramax 6.6L diesel is a solid, workhorse powerplant for GM’s heavy‑duty pickups, delivering strong low‑end torque and dependable towing capability. It remains a reliable choice for buyers who routinely haul heavy loads, though diesel ownership comes with higher maintenance costs and emissions‑system considerations.
What the engine is and who it serves
The 6.6L Duramax is GM’s turbocharged V8 diesel powering the Silverado 2500HD and Sierra 2500HD (and their 3500 variants in selected trims). For 2024, GM kept the engine as the cornerstone of its HD lineup, pairing it with a robust Allison 10‑speed automatic transmission and upgraded cooling and drivetrain components designed for sustained heavy use and long hauls.
Performance and Capabilities
These sections summarize the engine’s performance profile and how it translates to real‑world use for tow and work scenarios.
Power and Torque
These figures underpin strong pulling ability and stable highway performance. Specific outputs vary by configuration, but the 2024 Duramax in this application is positioned with a high‑torque, low‑rpm delivery intended for workhorse duty.
- Strong low‑end torque that helps with towing, hill climbs, and heavy accel under load
- Reliable power delivery when paired with the 10‑speed Allison automatic, which helps maintain momentum under heavy load
- Engine braking and smooth integration with the exhaust‑based retardation system for better control on descents
- Emissions controls (DPF and DEF‑system) designed to meet stringent standards without compromising drivability
In practice, the Duramax emphasizes torque and controllable power over headline horsepower, which suits its role in HD trucks intended for work and towing rather than sport performance.
Towing and Payload Capabilities
Real‑world towing and payload depend on the truck’s specific configuration, axle ratio, and cooling upgrades. GM’s HD lineup leverages the Duramax’s torque with a transmission and chassis designed to handle substantial tow and payload demands, including long grades and sustained highway pulling.
- High‑torque delivery that supports confident launches when towing heavy trailers
- Engine and transmission pairing engineered for repeated, long‑haul duty
- Integrated engine braking and drivetrain stability features to assist with control during long downhill pulls
- Diesel exhaust treatment designed to minimize performance penalties during regen events
Overall, the Duramax’s strength lies in reliable, sustained performance under load, making it well suited for commercial use, towing, and demanding work applications.
Maintenance, Reliability, and Ownership Costs
Diesel engines, including GM’s Duramax, require regular maintenance and attention to emissions components. Owners should expect DEF management, periodic fuel system service, and diesel‑specific oil changes with the correct Dexos/Dexos‑D fluids. The Duramax has a solid reliability track record in GM’s HD lineup, though ownership costs—such as fuel, maintenance, and potential repairs—tend to be higher than for typical gasoline engines. Warranty terms generally align with GM’s HD truck coverage, and many buyers stay current with manufacturer‑recommended service to optimize longevity.
Common watchouts include the diesel exhaust aftertreatment system, injector and turbo wear over long lifetimes, and potential DEF system quirks in extreme climates or with inconsistent fueling. Proactive maintenance and using recommended fluids help mitigate these issues and preserve long‑term durability.
Real‑world impressions and comparisons
Automotive press and owner feedback consistently highlight the Duramax 6.6L as a capable engine for heavy towing, with a broad torque curve that makes it less stressful to haul large loads than many gasoline rivals. Its main tradeoffs are higher purchase and operating costs, added complexity from emissions systems, and the need for diesel‑specific maintenance. When matched with the right heavy‑duty chassis and gearing, the Duramax remains competitive with its class peers in terms of capability and reliability.
Summary
For buyers who routinely tow heavy trailers, haul payloads, or work long distances with a truck, the 2024 Duramax 6.6L remains a strong, durable option. It delivers the torque and towing confidence HD buyers expect, backed by GM’s drivetrain integration and a proven Allison transmission. Those considering this engine should weigh the higher maintenance and fuel costs of diesel ownership against the proven performance benefits, and plan for emissions‑system upkeep as part of long‑term ownership.
Bottom line verdict
The 2024 Duramax 6.6L is a good engine for its intended role: a purpose‑built diesel for GM’s heavy‑duty pickups that prioritizes torque, reliability, and sustained work capability. If your needs revolve around serious towing and long‑haul durability, it remains a compelling choice; if you don’t require diesel grunt or are sensitive to diesel maintenance costs, a gasoline option or lighter‑duty setup may be a better fit.
How many MPG does a 2024 6.6 Duramax get?
21 is a good highway average empty in a 6.6 duramax. 8 maybe less fully loaded 18k+ towing. 24 -27 with wind in your favor empty.
Which Duramax to stay away from?
As for Duramax years to avoid, the 2011-2016 (LML) and 2004.5–2005 (LLY) have more frequent issues. The LML has CP4 fuel pump failures, so we recommend replacing it. The LLY is known to overheat, and potential solutions are maintaining proper airflow and coolant levels.
How reliable is the new 6.6 Duramax?
Many Duramax owners report reaching 300,000 miles or more with proper care, and some well-maintained engines have crossed the half-million-mile mark.
Are 2024 Duramax reliable?
The Duramax is known to many in the truck community as one of the most reliable motors, and GMC has been perfecting this motor since its conception in 2001. The reinforced nature of the Duramax motor means its components are not known to wear down prematurely like other gas-based engines found in competitive trucks.
