Are Paccar Diesel Engines Made By Cummins?

If you have even a passing interaction with the commercial trucking industry, chances are you're familiar with Paccar. You might not realize it since the company's name isn't as well-known as some of its brands, but if you know about Kenworth, DAF, or Peterbilt trucks you're familiar with Paccar. Paccar has a market cap — or total stock share value — of about $50 billion and is publicly traded on the NASDAQ stock exchange. That gives it tremendous influence on the trucking industry and plenty of resources to develop new technology. 

Similarly to how large car companies like Ford, the Volkswagen Group, and Stellantis have a persistent global presence, you 'll see Paccar semi-trucks on highways around the world. Paccar manufactures plenty of the engines that go in its trucks, but also uses a few made by its direct competitor Cummins. The best Cummins engines ever made include the X-15, which can be found in Paccar trucks like the Kenworth W900 Legacy Edition. In addition, some medium-duty Paccar engines are simply re-badged Cummins models made for use in Paccar's trucks. For example, the 8.9-liter PX-9 bears the Paccar name but is essentially a Cummins P9. So while Cummins doesn't make Paccar-branded engines, Paccar relies on Cummins to help power some of its trucks.

Paccar began business in 1905 under founder William Pigott, Sr. and Cummins was founded in 1919 by Clessie Cummins. Cummins began making diesel engines before the Great Depression and even provided an inline-six diesel engine for a 1952 Indy 500 race car. Cummins still produces pickup truck engines for Ram trucks, but hasn't limited itself to the pickup segment. Some years of the Cummins 6.7-liter turbodiesel engine have lifter issues, but it's remained popular despite this weakness.

Althogh Paccar is perfectly capable of building its own engines, the company has been working with Cummins in Europe since 1999 and North America since 2007. We included the X15N on our list of Cummins heavy-duty truck engines with the highest horsepower, and it's used in Paccar trucks like the Kenworth T680, Peterbilt 579, and Freightliner 114 and 112SD. There's also the Cummins X15 Performance Series engines, which Paccar features on the T680, 579, and Peterbilt 567. 

Paccar announced its partnership with Cummins in a June 2006 press release that noted, "The two companies are developing proprietary configurations for the engines, which will be badged as PACCAR engines." Cummins President CEO Joe Loughrey added, "This is an exciting development between two great companies and will enable Cummins and PACCAR to optimize the power train in medium-duty Kenworth and Peterbilt trucks." Prior to this agreement, Paccar had used rebadged 4- and 6-liter Cummins engines in some light-duty European DAF brand trucks.

The larger Paccar PX-6 engine is based on the 6.7-liter Cummins ISB, produces between 200-325 horsepower, and can be certified for Euro emissions levels 2 through 6. The original Cummins ISB debuted in 1998 as a 5.9 liter inline-six; that version produces between 215 and to 325 horsepower. As for the 6.7-liter ISBe, it makes up to 385 horsepower and 900 pound-feet of torque. Paccar's rebranded engines are functionally identical to the Cummins engines they are based on, but Paccar hasn't given up on developing and producing its own diesel powerplants. The Seattle -area company still makes MX series diesel engines, including the MX-13 and MX-15.