What Are The Best Diesel Engines: Find Out Here!

There are a plethora of diesel engines out there. So, it can be confusing to choose a high-quality one. However, after a lot of time has passed and after many tests, several diesel engines proved to be the best diesel engines on the market. These diesel engines passed tests with qualifying questions, such as:

  • How is the compression on the diesel engine?
  • How long does the diesel engine last?
  • How many glow plugs does it use?

The following are five of the best diesel engines out there. These engines excel in top-notch quality regarding compression, glow plugs, and much more.

The 5 Best Diesel Engines

1.      Ford 6.7L Powerstroke

Navistar International manufactured Ford’s power stroke diesel. It was the first medium-duty diesel directly manufactured for Ford. This diesel engine was created as a savior of the 6.0L and 6.4L, thus becoming one of the best diesel engines for Ford.

The Ford 6.7L Powerstroke diesel engine initially had a torque of up to 735 Ib-ft and 379 horsepower. Now, it is upgraded to a torque that goes up to 800 Ib-ft and engine power that goes up to 400 horsepower. And due to its exhaust manifold and turbo mounted in the valley of the engine, the engineers at Ford nicknamed this engine the “Scorpion”.

The Ford 6.7 Powerstroke engine.

Ford has done an extraordinary job with this diesel engine, which has impressive fuel economy, performance, longevity, and reliability. Its engine includes a compacted graphite iron (CGI) block.

This feature is for greater strength while reversing flow aluminum cylinder heads with six head bolts per cylinder, and dual water jackets. This feature is also for a 29,000 psi high-pressure common rail Bosch fuel system.

When it comes to its fuel injection system, this product delivers up to five injection events per cylinder for each cycle. It does this by utilizing eight-hole piezo injectors that spray into the piston bowl.

Also, this engine supports B20 biodiesel, which allows greener fueling options of up to 80 percent of petroleum diesel and up to 20 percent of biodiesel.

More details of this product’s specifications and features include the following:

2.      6.7L Cummins V8

Released by Cummins Inc., the 6.7L Cummins V8 is one of the best engines to handle heavy hauling. This diesel engine provides the most torque available in non-commercial vehicles. The 6.7L Cummins V8 is made for Dodge Ram and it is a favorite as a foundation to produce a super-powerful diesel racing engine with tuned-up units creating a reliable 3,000 hp.

The 2022 Ram 3500 running an engine diesel.

This diesel engine is the replacement for the aging 24-valve, 5.9L Cummins. The 5.9L Cummins proves to be incompetent to keep up with increasingly stringent emission standards. With the new 6.7L Cummins, vehicles will have the same heads and cast-iron blocks as the 5.9L Cummins had but the 6.7L Cummins features a wealth of air/fuel delivery technology.

In 2007, Cummins Inc. introduced the latest-B series engine, which is the 6.8-liter V8 diesel engine. This engine produces an output of 900 Ib-ft of torque and 385 hp in factory specification which makes it a muscular engine. In 2013, this engine had additional upgrades by being equipped with SCR (Selective Catalyst Reduction).

With SCT, the torque increased by 10% in the 6.7L while also slashing the engine’s overall output of emissions. In 2021, this diesel engine made a peak torque output in excess of 1.075 Ib/ft.

The following includes more details of the features and specifications:

3.      Chrysler 3.0L EcoDiesel 1-6

The parent company of Chrysler FCA chose the 3.0L EcoDiesel to be a diesel engine for both the Jeep Grand Cherokee and the RAM 1500 in 2014. VM Motori, a subsidiary of FCA, manufactured this engine, and VM Motori is located in Cento, Italy. After the 2019 Jeep Grand Cherokee model year, the 3.0L EcoDiesel was no longer in the Jeep Grand Cherokee. This engine, however, is still in the RAM 1500.

This engine includes a compacted graphite iron (CGI) engine block. It is a 60-degree angle between cylinder banks. The CGI blocks are lighter, stronger, and more compact than cast iron blocks.

For extra strength, the engine block includes a bedplate, which has four 14mm bolts for each main and additional eight 12 mm bolts that hold down the bedplate. Inside the engine is cast iron connecting rods, a forged 4140 steel crankshaft, and cast aluminum pistons.

EcoDiesel is small but mighty even though it’s the industry’s lone light-duty diesel engine.

More specifications of the 3.0L EcoDiesel I-6 are as follows:

4.      7.3L Ford Power Stroke

The 7.3L Powerstroke became the most reliable diesel engine after its release in 1994. And after approximately three decades after its debut, the 7.3L Powerstroke is still widely considered one of the most reliable diesel engines.

The 7.3L Powerstroke possesses an unparalleled degree of reliability. This engine was a joint venture product between Ford and International Navistar (now Navistar International), and it is manufactured for Ford’s heavy power-packed trucks.

Also, this diesel engine includes a technology known as Hydraulic Electric Unit Injection (HEUI). This technology assists in eliminating without needing a solely dedicated injection pump. High-pressure engine oil replaced the injection pump to create hydraulic pressure in every injector for injecting low-pressure fuel. It does this under substantial force.

The diesel engine is unique and strong. It is a legendary workhorse that is definitely up to the job. It can overcome loads due to the engine’s specifications/features.

In fact, these specifications/features are as follows:

5.      6.6L Duramax L5P

Introduced in 2017 by Chevrolet, the 6.6L Duramax L5P was built to replace the earlier LML Duramax. This diesel engine is the choice as the heavy-duty powerplant for GMC and Chevrolet pickups’ HD-series. And in comparison to earlier Duramax diesel engines, the L5P is notable due to its use of a new variable-vane turbocharger, an updated camshaft, and revised cylinder heads.

Please note, however, that the displacement of the 6.6L Duramax L5P is practically all that is similar to the older LML. It is a great representation of the past production of Duramax with most of its torque being produced at the lower RPM ranges, i.e. 90% at 1,550 RPM.

The 6.6L V8 L5P turbo diesel engine.

And with the exception of the L5P’s newly found, hood-scoop, it does have a closely similar appearance to the LML Duramax. This diesel engine, however, has significantly better towing ratings, reliability, and performance specs. Also, many of these features proved to be highly beneficial in critical service towing applications.

This new Duramax diesel engine is the most capable diesel engine of this brand. It produces 910 Ib-ft of torque and 445 horsepower in stock form. One of its changes includes a fully functional hood scoop intake system, a fuel system overhaul, and a Borgwerner Variable Geometry Turbocharger.

Other specs and features that make the L5P impressive, include the following:

Which Diesel Engine is the Most Reliable?

Diesel engines in general are more reliable than gas engines. So, of course, these five diesel engines are among the most reliable diesel engines. The best of best of these diesel engines, however, is the 6.7L Cummins V8.

In 2019, Cummins Inc. celebrated its 30-year partnership with RAM truck with the Cummins 5.9L Turbo Dieslel. The 6.7L Cummins Turbo Diesel in 2021, however, brought more torque and horsepower while maintaining this diesel engine’s historic efficiency and durability.

Recently, RAM stated that the 6.7L Cummins can go up to 350,000 miles. So, with routinely scheduled services and no performance modifications on this engine, this mileage is guaranteed.

Which Diesel Engine Lasts Longer?

Diesel Engines are known to last the longest than gasoline engines due to their cylinder wall, bearings, pistons, and other features. So, while diesel engines last longer than gas engines, these five diesel engines are considered the best overall when it comes to longevity. And of those five diesel engines, the one that lasts the longest is the 7.3L Powerstroke.

The 7.3L Powerstroke became the most reliable diesel engine after its release in 1994, and it is still widely considered one of the most reliable diesel engines. The 7.3L Powerstroke also has tons of power for most applications.

It comes with 235 horsepower and 500 pound-feet of torque. It is also built for the long haul which comes with oil-based fueling, durable internal hard parts, and an air-to-air intercooler.

For those looking for a used 7.3L Powerstroke, they can purchase one with great peace of mind. When it comes to a 1999 to 2003 Super Duty 7.3L Powerstroke that is properly maintained, for instance, it can go beyond 500,000 miles.

So, getting one in good condition with 150,000 to 250,000 is well worth it. This diesel engine has very durable internals, no complicated emissions control systems, and tons of widely available parts.


Several diesel engines proved to be the best diesel engines on the market. Five of the best diesel engines out there are the Ford 6.7L Powerstroke, 6.7L Cummins V8, Chrysler 3.0L EcoDiesel I-6, 7.3L Ford Power Stroke, and 6.6L Duramax L5P.

Diesel engines are generally more reliable than gas engines. So, of course, these five diesel engines are among the most reliable diesel engines. The best of these diesel engines, however, is the 6.7L Cummins V8.

Diesel Engines are also known to last the longest than gasoline engines. However, the one that lasts the longest is the 7.3L Powerstroke.

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About Matthew Webb

Hi, I am Matthew! I am a dedicated car nerd! During the day, I am a journalist, at night I enjoy working on my 2 project cars. I have been a car nerd all my life, and am excited to share my knowledge with you!

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