PACCAR PX-7 engine: displacement, ratings and generations

The PACCAR PX-7 is a 6.7-litre six-cylinder in-line engine. PX-7 is a trademark of PACCAR Inc., and the engine is documented by DAF in Europe and by PACCAR’s own specification sheets in the United States. DAF presented a completely redesigned PX-7 for its LF in October 2022, with four ratings from 167 kW (230 hp) to 227 kW (310 hp) and 900 to 1,200 Nm, and added it to the XD and XB in 2023; in the United States PACCAR’s sheets give EPA 2021 and EPA 2024 certification at 200 to 360 hp. On this site it is one of the engines of the DAF XB, the DAF XD and the Tatra Phoenix.

Status as of 26 October 2026. Read that day: five DAF press releases from 16 July 2015 to 20 November 2023, and PACCAR’s EPA 2021 and EPA 2024 PX-7 specification sheets, published on Peterbilt’s site.

Maker, name and layout

PACCAR’s 2021 specification sheet states that “PX-7 is a trademark of PACCAR Inc.” DAF writes the name as PX-7, as PX7 in the headline of its July 2015 release and as PX 7 in the headline of its release of 5 June 2023. The PX-5, a separate 4.5-litre four-cylinder engine that DAF introduced together with the redesigned PX-7, is not covered here.

PACCAR’s US sheets give the layout as “Inline 6-cylinder” with a displacement of 6.7 litres and a bore and stroke of 107x124 mm. For the redesigned engine of 2022, DAF lists a Compacted Graphite Iron (CGI) block, a cast-iron cylinder head, low-friction pistons, new compressors and “a new waste-gate turbo”; its XD release of 5 June 2023 calls the PX-7 a “non-EGR engine”.

Engine brakes and retarders in general are covered in retarders and engine braking.

Ratings as the maker states them

Europe: DAF

DAF’s release of 6 October 2022 for the LF and its release of 23 August 2023 for the XB print the same table of four PX-7 ratings, each with a torque figure and an engine-speed band. The XD release of 5 June 2023 lists the same four outputs.

Before the redesign, DAF’s release of 16 July 2015 gave the PX-7 of its three-axle CF models as having “power ratings of 208 kW/283 hp or 231 kW/314 hp”, without torque figures. How kW, hp and Nm relate, and what the engine speed beside a torque figure means, is explained in reading truck power figures.

United States: PACCAR’s EPA specification sheets

PACCAR’s sheets for EPA 2021 and EPA 2024, published on Peterbilt’s site, present the PX-7 for “medium-duty customers” and state that it “is available in horsepower ratings from 200 to 360” hp, with 520 to 800 lb-ft of peak torque and a governed speed of 2,600 RPM. The rating tables of the two sheets are not identical. The 200 hp rating is listed with 520 lb-ft at 1,600 rpm on the 2021 sheet and with 600 lb-ft at 1,300 rpm on the 2024 sheet. On the 2021 sheet the top rating, 360 hp with 800 lb-ft at 1,800 rpm, carries the footnote “Fire Service Rating Only”.

Generations

The documents read for this page reach back to July 2015, when the PX-7 was already part of DAF’s Euro 6 CF range; none of them dates the engine’s first introduction. In the United States PACCAR’s sheets are identified by their certification years.

2015: the Euro 6 CF

On 16 July 2015 DAF announced that it “now also supplies the Euro 6 CF with the PACCAR PX-7 engine in a number of models with three axles”. The release gives the engine as “the 6.7-litre six-cylinder PACCAR PX-7 engine that has power ratings of 208 kW/283 hp or 231 kW/314 hp”, with a nine-speed manual gearbox as standard and a 12-speed AS Tronic automated gearbox at extra cost, and says production of the new models would start in early November.

2022: the redesigned engine

DAF’s release of 6 October 2022 introduced new drivelines for the LF series and states: “The 4.5 liter 4-cylinder PACCAR PX-5 engine and the 6.7 liter 6-cylinder PACCAR PX-7 engine have been completely redesigned.” It lists the CGI block, cast-iron cylinder head, low-friction pistons, new compressors and waste-gate turbo described above, gives the PX-7 outputs “from 167 kW (230 hp) up to 227 kW (310 hp)”, and pairs both engines with new automatic 8-speed PowerLine gearboxes.

2023: the DAF XD and XB

On 5 June 2023 DAF added the PX-7 to the New Generation XD, first “as a 4x2 rigid with Day Cab”, in the four ratings above and with a new 8-speed, fully automatic PowerLine transmission. On 20 November 2023 DAF extended the XD with PX-7 to wheelbases “of up to 6.9 metres” and to the Sleeper Cab and Sleeper High Cab, and described the PX-7 driveline as intended “for up to 19 tons applications”.

On 23 August 2023 DAF announced the New Generation XB, a series of distribution trucks “in the 7.5 up to 19 tonnes class”, with 4.5-litre PX-5 and 6.7-litre PX-7 engines alongside battery-electric versions. The release prints the same four PX-7 ratings and says the XB “will enter production in the fourth quarter of 2023”.

EPA 2021 and EPA 2024 in the United States

PACCAR’s two US sheets carry the certifications “EPA 2021” and “EPA 2024”, sheet codes 2021PACCARPX7SPEC and 2024PX7SPEC. Both give 6.7 litres, an inline six-cylinder layout, 107x124 mm, 200 to 360 hp and 520 to 800 lb-ft.

Fuels and emission class

None of the documents read for this page calls the PX-7 a diesel engine or lists a natural-gas version; the fuel statement they do make is about HVO.

• HVO. DAF’s XB release of 23 August 2023 states: “The PACCAR PX-5 and PX-7 engines are ready for the application of HVO, reducing CO₂ emissions with up to 90% (‘well-to-wheel’).” What HVO is and which standard it follows is covered in what is HVO fuel.
• Europe. DAF’s release of 16 July 2015 describes “the Euro 6 CF with the PACCAR PX-7 engine”, and an image in the same release is captioned “DAF PACCAR PX 7 engine EURO 6”. The 2022 and 2023 releases read for this page do not name an emission standard or a Euro VI step for the redesigned engine. The steps from Euro VI A to E and what Euro 7 adds are covered in Euro VI and Euro 7.
• United States. PACCAR’s specification sheets give “EPA 2021” and “EPA 2024” certification.

Trucks and buses on this site with the PACCAR PX-7

Three model pages on this site list the PACCAR PX-7. The figures below are those of each model’s own page and the maker’s source that page cites, as each page records the engine; they are not the engine-level tables above. The DAF XD page records 890 to 1,190 Nm, where DAF’s releases of 6 October 2022 and 23 August 2023 print 900 to 1,200 Nm.