3.0L LM2 Duramax Specs, Fuel Economy, and Towing Capacity (2024)

Comprehensive 3.0L Duramax Diesel Engine Guide

Until recently, half-ton pickup trucks were typically equipped with big, bulky V-8 engines powered by gasoline. These engines offered terrible fuel economy and sluggish performance. That isn’t the case anymore though. With the help of turbochargers and improved technology, pickup trucks are more powerful, they have better fuel economy, and they are more environmentally friendly than ever before. GM’s 3.0L LM2 Duramax Diesel engine is a prime example of this. Despite being a tiny, inline-6 diesel engine, the 3.0L LM2 Duramax has some very impressive performance, towing, and fuel economy specs. We go over more details about this latest Duramax engine down below.

3.0L Duramax History

Although GM was the first to offer a diesel in a mid-size truck, the 2.8L LWN Duramax found in the Duramax Colorado or Canyon, they were the last to adopt a half-ton diesel. The 3.0L Duramax diesel engine was originally introduced in 2020, on the Chevy Silverado 1500 and GMC Sierra 1500. In 2021, the new Duramax was made as an available powertrain on full-size GM SUVs. That includes the 2021 Tahoe, Suburban, Yukon, and the Escalade.

3.0L LM2 Duramax engine introduced in 2020

GM released their 3.0L LM2 Duramax Diesel engine. It’s made an available powertrain option on Silverado 1500 and Sierra 1500 half-ton trucks. – Photo taken from Chevrolet Media Website

3.0L Duramax Joins SUV Lineup in 2021

In 2021, the 3.0L LM2 Duramax Diesel engine joins GM’s Full-size SUV lineup. It became an available powertrain option on 2021+ Chevrolet Tahoes and Suburbans, GMC’s Yukon and Yukon XL, and Cadillac’s Escalade.
– Photo taken from Chevrolet Media Website

3.0L LM2 Duramax Engine Design

The 3.0L LM2 Duramax Diesel engine utilizes an inline-six cylinder design. GM chose this design because it uses less space, it offers greater efficiency, and it provides smooth operation. When compared to DOHC V-6 engines, it benefits from reduced friction internally. Inline-6 designs have proven themselves to be capable on both the longevity and performance fronts in diesel engines. Just think of the famous 5.9L or 6.7L I-6 Cummins diesel engines that have powered Ram Heavy Duty trucks since the late 1980s.

The Block

The LM2 3.0 Duramax engine block is made of cast aluminum alloy. This helps maintain durability while simultaneously reducing mass 25% compared to similar CGI blocks. Iron cylinder liners are present within the block to ensure durability. The block itself has a deep-skirt design, where the block casting extends below the crankshaft line. Seven nodular iron main bearing caps further improve block reliability and help combat the high, sustained combustion pressures of a diesel engine. These caps also enable precise location of the rotating assembly.

Rotating Assembly

The rotating assembly used in this engine are also similarly heavy-duty. It’s made up of a Forged steel crankshaft, forged-steel connecting rods, and hypereutectic aluminum pistons. Silicone is blended with the aluminum in the piston cylinders for improved heat tolerance and resistance, resulting in greater noise reduction and performance. The top of the pistons features a thick, piston crown and a reinforced top ring. This helps bolster the pistons against the high cylinder pressures attributed to the turbocharger and the engine’s 15.0:1 compression ratio.

Cylinder Head

3.0L LM2 Duramax engines have a DOHC cylinder head made of lightweight aluminum for reduced weight. A dual overhead camshaft design is used because it offers a direct and efficient means of controlling the valves. Each cylinder has 4 valves. Finger-followers with hydraulic lash adjusters regulate air flow in and out of the engine.

Rear Cam Drive

A unique attribute of this 3.0L Duramax diesel is that it features Rear cam drive. Rear Cam Drive means the camshaft drivetrain is located on the back of the engine (towards the firewall of your truck). This was done for “packaging considerations and greater refinement”, according to GM. The drive system works as follows. A crankshaft-driven chain powers the high-pressure fuel injection pump. The fuel pump’s chain then drives the two camshafts. Last, there’s a smaller belt that drives the variable flow oil pump from the crankshaft.

3.0L LM2 Duramax Performance Specs

The 3.0L LM2 Duramax turbocharged diesel engine is unique when compared to its rivals. Both the 3.0L Powerstroke and the 3.0L EcoDiesel use V-6 engine designs. Instead of following this same pattern, the six-cylinder Duramax uses an inline design. This provides a smoother driving experience and less friction internally. It also helps reduce mass inside the engine bay. While these aren’t number you can see on a spec sheet, they result in better performance that is worth mention.

The 3.0L Inline-6 Duramax produces 277 horsepower and 460 lb-ft of torque. It also offers impressive towing specs with a max tow capacity of 9,500 lbs on pickup trucks and 8,200 lbs on SUVs. Despite having a lower maximum towing capacity than the 5.3L V-8 or 6.2L V-8 gasoline-powered engines, the 3.0L Duramax still has one significant advantage. It reaches 95% of peak torque at only 1,250 rpm. At 1,500 rpm it reaches max torque and it then largely maintains it until about 3,000 rpm.

Despite these pretty impressive numbers, achieving the highest horsepower or towing capacity wasn’t GM’s goal for the new 3.0L Diesel, fuel economy was. On half-ton trucks and full-size SUVs the 3.0L Duramax dominates fuel economy when compared to both competitors and even GM gasoline-powered counterparts. Skip to our fuel economy section for EPA estimated fuel mileage. In our next section, we’re going to go over the critical components of the 3.0L Duramax Turbodiesel engine that make its favorable performance a reality.

Key Performance Characteristics

For this small diesel engine to be fuel efficient, powerful, and keep emissions in check, GM had to get creative. A variable geometry turbocharger is used, that is accompanied with a water-to-air intercooler for cooler, denser air. This maximizes performance while also helping to reduce emissions. To further reduce emissions a low-pressure EGR system was added. GM also uses a high-pressure direction injection common rail fuel system. It operates at 2,500 bar or 36,250 psi and provides precise fueling for optimal noise and performance. In addition to these features, a 10-speed automatic transmission brings it all together, bringing the power to the ground smoothly. Here’s how all these features help make the 3.0L Duramax successful.

Air Induction System

The 3.0L Duramax engine uses a highly advanced VGT or variable geometry turbocharger for improved performance and efficiency. It automatically adjusts boost pressure according to demand and driving conditions. This ability is attributed to its sophisticated electronic controls. This turbocharged is also liquid-cooled and it has a low-friction ball bearing shaft. For quicker spool times, the turbocharger is placed close to the engine’s exhaust outlet.

A water-to-air intercooler is also found on this powertrain. It provides cooler, denser air to the engine for combustion. This results in a cleaner burn and more power. Maximum boost pressure is 43,5 psi, or 300 Kpa absolute.

3.0L LM2 Duramax Diesel Emissions

A number of emissions devices are found on every diesel now. They’re used to reduce the amount of harmful emissions from the tailpipes of diesel vehicles. The 3.0L LM2 Duramax Diesel has a Diesel Oxidation Catalyst (DOC), Diesel Particulate Filter (DPF), Selective Catalytic Reduction (SCR) system, and a high/low pressure EGR system.

Enter the Low-Pressure EGR System

While most of these emissions devices are pretty standard, the EGR system is a new design. Traditionally EGR systems re-route exhaust gases between two points of higher pressure, the intake manifold and the exhaust manifold. This essentially means there’s really only a high-pressure EGR system. According to GM, this is a problem because sufficient exhaust gas flow can often require help from the turbocharger or other components. This results in efficiency loss.

The 3.0L LM2 Duramax Diesel engine features a low-pressure EGR system to supplement the existing high-pressure system. This helps improve efficiency and performance. Basically exhaust gases are drawn from after the diesel particulate filter and re-introduced after the compressor inlet. An electronically controlled valve activates the low-pressure EGR system, the engine burns exhaust gases that have already passed through the filter. The end result is even lower emissions and more components that are expensive and can break on your truck.

Fuel System

The LM2 Duramax Diesel engine’s fuel system uses common rail direct fuel injection. At the heart of this fuel system is an engine-driven twin-piston pump. This pump sends fuel to the solenoid-activated injectors with 9-hole nozzles. These nine-hole nozzles produce a more precise fuel spray that results in lower noise and smooth idling. Up to 10 injections per injector can occur during a combustion cycle.

10-Speed 10L80 Automatic Transmission

The Hydra-Matic 10-speed automatic transmission, also known as the 10L80, is a transmission that was designed in cooperation with Ford Motor Company. In fact, the 3.0L LM2 Duramax’s rival, the 3.0L Powerstroke, uses a variation of this transmission with a different name, the 10R80.

The 10L80 transmission uses a centrifugal pendulum absorber torque convert. This reduces vibrations and provides a smoother ride. This helps with GM’s quest to reduce NVH on their trucks. On 3.0L Duramax trucks it also has a feature that many of us diesel lovers are familiar with, engine braking. When drivers select the tow/haul mode, exhaust braking occurs which basically uses the engine’s compression and aggressive downshifting by the transmission to reduce speed without touching the brakes. This is a huge help when towing!

Another characteristics of the 10L80/3.0L Duramax matchup is stop/start technology. City driving or idling is a killer of modern diesel engines. It can cause excessive regenerations to occur, ultimately resulting in lower fuel economy and eventually a clogged diesel particulate filter. This features should significantly help Duramax owners who live in more urban areas.

Other Useful LM2 Duramax Features

Improved Oiling System

GM wasn’t only concerned with fuel economy and providing a capable engine. They wanted to make the new 3.0L LM2 Duramax reliable too! To help accomplish this, they provided this engine with a state-of-the-art oiling system. The LM2 Duramax has a variable-pressure oiling system with a variable displacement oil pump that matches oil pressure to demand and load.

Oil Jets found in the block are another feature that help improve engine durability. These jets target the inner core of the pistons, with extra cooling, lubricating oil. This reduces piston temperatures, therefore improving longterm durability and performance.

Cold Weather Superstar

The LM2 Duramax features new technology that makes it perform very well in colder weather. Cold starts? No problem. This engine uses ceramic glow plugs that heat up more quickly and get hotter than traditional metal glow plugs. This results in the engine starting easier in colder weather. These help the 3.0 Duramax achieve unassisted starting at -22 degrees Fahrenheit, or assisted starting at -40 degrees Fahrenheit.

Ceramic glow plugs aren’t the cold weather-friendly feature of the LM2. Active thermal management helps the engine warm up quicker and it helps maintain ideal engine temperatures for better performance too. A 3-Actuator rotary valve sends coolant throughout the system whether additional heat or cooling is necessary. This feature doesn’t just help in cold weather situations. Under heavy load, this system helps bring engine temperatures down by providing extra coolant.

3.0L LM2 Duramax Specs

Here’s a detailed chart depicting 3.0L LM2 Duramax Engine Specs.

3.0L LM2 Duramax Fuel Economy

2020+ Silverado 1500 and Sierra 1500 Diesel MPGS

GM’s 3.0L Duramax Diesel engine gives Silverado 1500 and Sierra 1500 owners up to an estimated 33 miles per gallon on the highway and 23 in the city. These high fuel economy ratings will be on two-wheel drive models. Four-Wheel Drive models are capable of 29 miles per gallon on the highway and 23 miles per gallon in the city.

GM Full-size SUVs like the Chevrolet Tahoe and Suburban, GMC Yukon and Yukon XL, and the Cadillac Escalade gained the 3.0L Duramax as a powertrain option in 2021. The 3.0L Duramax offers significantly better fuel economy than the 5.3L Gas V-8 or the 6.2L V-8 gasoline engines available on these vehicles. Check the chart below for fuel economy estimates from the EPA.

2021+ GM Full-Size SUV Fuel Economy

Fuel Tank Size 3.0 Duramax Silverado 1500 & Sierra 1500

3.0L LM2 Duramax Towing Specs

The 3.0L Duramax doesn’t have the highest towing specs available in Silverado/Sierra 1500 trucks or their full-size SUVs, but I still consider it a solid option for frequent towing. It has a unique advantage over the 6.2L V-8 and 5.3L Vortec V-8 engines because of its inline-6 cylinder design, and the fact that it is a turbodiesel engine. Diesel engines reach max torque much sooner than gasoline engines. The 3.0L LM2 Duramax reaches 460 lb-ft of torque at only 1,500 rpm. Compare this to the 6.2L V-8 engine that reaches peak torque of 460 lb-ft at 4,100 rpm.

Fuel economy is also much better when towing in diesel trucks. If you’re towing frequently, especially while driving on the highway, the 3.0L Duramax is a good fit for you. Under city driving conditions, this diesel engine could actually be disadvantageous. Modern emissions on diesel engines cause poor performance in city conditions or while idling. You could experience frequent regens, killing fuel economy and using more diesel exhaust fluid. This could be a non-issue however, at the 3.0L Duramax features stop/start technology.

3.0L LM2 Duramax Towing Capacity

While the 3.0L Duramax does provide higher estimated fuel ratings than the 3rd generation EcoDiesel or the 3.0L Powerstroke F150, it offers less tow capacity. Max tow capacity for the 2020 Silverado 1500 or 2020 Sierra 1500 is 9,300 lbs. In 2021, this is increased to 9,500 lbs on 2WD models. Tow capacity will vary according to your trucks specifications, so it’s important to consult your owners manual or GM directly to get your exact max tow capacity.

On GM full-size SUVs the tow capacity varies according to which vehicle you purchase. Look at the chart below for a breakdown of 3.0L Duramax max towing capacity.

3.0L LM2 Duramax FAQ

Want to learn more about the new 3.0L Duramax?

Check out our other articles about the 3.0L Duramax. You can also visit the Chevrolet or GMC press release about the new 3.0L Duramax by clicking one of the links below.

• 3.0L LM2 Duramax Service Schedule Guide

Chevrolet Press Release

GMC Press Release