3.0-liter Duramax or 6.6-liter Duramax: Which Is Best for You?

Diesel engines aren’t as widely available on dealers’ lots as they were several years ago, but they remain the go-to option for heavy-duty trucks (HD) and towing machines. Chevrolet and GMC are the two lone automakers still offering a diesel option in a light-duty pickup truck, as the Silverado 1500 and Sierra 1500 are both available with a turbocharged Duramax 3.0-liter turbodiesel inline-six. The two brands’ HD trucks can be optioned with a Duramax 6.6-liter turbodiesel V8. While they are both diesel engines, there are a few key differences to be aware of, so let’s take a closer look. 

The Main Difference Is Heavy- Versus Light-Duty Trucks 

The V8 Duramax diesel is only available in Chevy and GMC’s HD trucks, which means a 2500 or 3500 model, while the inline-six comes in light-duty 1500 trucks. While both are extremely capable engines, the Duramax V8’s 470 horsepower and 975 pound-feet of torque make it significantly more potent than the six-cylinder engine. It produces 305 horsepower and 495 pound-feet of torque. The V8’s massive torque enables up to a 36,000-pound maximum towing capacity, making the HD trucks a go-to choice for people needing to pull heavy loads. The diesel inline-six-equipped 1500 pickups can tow up to 13,300 pounds.  

Transmissions and Other Differences 

The Duramax V8 is paired with an Allison ten-speed automatic transmission. The Allison brand is known for building super-robust transmissions for the most hardcore applications, and the ten-speed in General Motors’ diesel-equipped HD trucks is designed to withstand the heavy towing and hauling people do with their pickups. That’s not to say that the ten-speed automatic that comes with the diesel inline-six isn’t robust, but it’s designed for a much less grueling workload. 

Heavy-duty trucks equipped with the Duramax get a functional hood scoop that aids airflow to the engine. The diesel-equipped 1500 pickups do not get a hood scoop due to the smaller engine’s reduced airflow needs. Fuel economy is a strong point for the smaller engine, however, as it achieves up to 29 mpg, while the V8 averages much less than that. That said, it’s important to note that the EPA does not officially rate fuel economy for heavy-duty or commercial vehicles. 

If you’d like to learn more about diesel trucks or any other new or pre-owned model, come see us at Sharp Automotive. Our knowledgeable staff would be excited to walk you through the capabilities of the various truck powertrain options, schedule a test drive, or order the new truck of your dreams.