PACCAR MX-13 engine: displacement, ratings and generations

The PACCAR MX-13 is a 12.9-litre six-cylinder in-line turbocharged diesel engine. It carries the name of PACCAR Inc., which holds the MX-13 trademark and whose companies include DAF Trucks and Peterbilt; DAF builds it in Eindhoven and DAF Components, DAF’s component-supply business, supplies it to other manufacturers. In Europe it is a Euro 6 engine of 315 to 390 kW, and DAF introduced “new PACCAR MX-11 and MX-13 engines” with its New Generation trucks in 2021; in North America PACCAR certifies it to EPA 2021 and EPA 2024 at 405 to 510 hp, and a CARB low NOx version followed in 2024. On this site it is one of the engines of the DAF XF, XG and XG+, the Tatra Phoenix and the Irizar i6S.

Status as of 26 October 2026. Read that day: DAF Components’ MX-13 infosheet for model year 2025, its MX-13 truck-engine page and its MX-13 coach and bus page; eight DAF press releases from 9 June 2021 to 29 September 2025; DAF’s alternative-fuels infosheet; PACCAR’s EPA 2021 and EPA 2024 MX-13 specification sheets, published on Peterbilt’s site; and Peterbilt’s release of 4 June 2024 on the CARB low NOx MX-13. All are documents of PACCAR or its companies.

Maker, name and layout

PACCAR’s US specification sheets state that “PACCAR MX, MX, MX-11, and MX-13 are trademarks of PACCAR Inc.” DAF’s release of 7 July 2025 calls them “PACCAR MX-13 engines built by DAF in Eindhoven”, and its Busworld 2025 release describes DAF Components as an independent supplier of “components, such as engines, axles and cabs to manufacturers of buses, coaches, specialised vehicles as well as ships all over the world”. The MX-11, a separate 10.8-litre engine, is not covered here.

The engine is named by family and rating. DAF Components lists the truck versions as MX-13 315, MX-13 355 and MX-13 390, the figure being the output in kW; DAF’s fuels infosheet names the biodiesel version “MX-13 480 B100”; PACCAR’s US sheets mark multi-torque ratings “MT”; and Peterbilt offers a “CARB low NOx” version. DAF Components’ 2025 infosheet also marks two model years with a code in its compression-ratio entry, “MY24 - 03670” and “MY25 - 03683”, and calls 03683 an option.

DAF Components gives the layout as a “six-cylinder in-line turbocharged diesel engine with intercooling”, with exhaust gas recirculation (EGR), a diesel particulate filter (DPF) and selective catalytic reduction (SCR) “aftertreatment for Euro 6 emission levels”. How SCR and AdBlue work is covered in SCR and AdBlue explained.

Ratings as the maker states them

Euro 6 trucks: DAF Components

DAF Components’ infosheet for model year 2025 and its truck-engine page list three ratings. Each has two torque figures; the higher one, in the infosheet’s footnote, applies “In the highest gear for direct drive gearboxes and in the two highest gears for overdrive gearboxes”. The infosheet’s charts carry the labels “Multi Torque” and “ECE R24-03 (ISO 1585) EURO 6”.

The truck-engine page prints the same figures and gives each rating’s emission level as “Euro 3/5/6”, with the footnote: “Engines with Euro 3 or 5 emission levels have different torque and power (curve) settings.” It gives no figures for those settings.

How kW and hp relate, and what the engine speed beside each figure means, is explained in reading truck power figures.

Coaches and buses: DAF Components

DAF Components’ coach and bus page lists the same three outputs, 315 kW / 428 hp and 355 kW / 483 hp at 1,600 rpm and 390 kW / 530 hp at 1,675 rpm, with a single torque figure each: 2,300, 2,500 and 2,700 Nm, all printed “at 900-1125 rpm”, and Euro 6 for all three. It states power “according to ISO 1585”, a high idle speed of 2200 rpm and an idle speed of “550 +50 -25” rpm. DAF’s releases of 4 October 2023 and 29 September 2025 give the coach and bus MX-13 as “315 kW/428 hp up to 390 kW/530 hp”.

United States: PACCAR’s EPA specification sheets

PACCAR’s specification sheets for EPA 2021 and EPA 2024 list the same seven ratings, from 405 to 510 hp and from 1,550 to 1,850 lb-ft. Three are multi-torque ratings with two torque figures.

The sheets mark MT as “Multi-torque rating”. The CARB low NOx version has two ratings, which Peterbilt gives as 510 hp with 1,850 lb-ft and 455 hp with 1,650 lb-ft “between 900 and 1,325 RPM”.

Generations

The documents read for this page date the MX-13 from the New Generation DAF engines of 2021 onward; none of them dates an earlier MX-13. In North America PACCAR’s sheets are identified by their certification years.

2021: the New Generation DAF engines

DAF’s launch release of 9 June 2021 names “the introduction of the new PACCAR MX-11 and MX-13 engines” as part of the New Generation DAF XF, XG and XG+, with production to begin in October. DAF’s release of 4 November 2021 marks the start of series production in Eindhoven: the official “Job One” truck was an XG+ “with a 12.9 litre PACCAR MX-13 engine”.

2023: the coach and bus series

On 4 October 2023 DAF Components introduced “a completely new series of PACCAR MX-11 and PACCAR MX-13 engines for coaches and buses”, based on the engines DAF had introduced for its XD, XF, XG and XG+ trucks. The release says the combustion of the 12.9 liter MX-13 “has been optimized through the use of new injectors, a new cylinder head and block and a new design of pistons and liners”, with a new generation of turbochargers and new air compressors, oil pumps and alternators. For the MX-11 and MX-13 together it states: “Maximum torque has been further increased by 50 to 150 Nm and is already available at 900 rpm.” The release announced their first appearance for Busworld 2023 in Brussels, 7 to 12 October 2023.

2024: engine updates

DAF’s release for the IAA Transportation 2024 of 16 September 2024 and its release of 10 October 2024 list “PACCAR MX-11 and MX-13 engine optimizations”: new engine valve timing following the Miller principle, a dual drive coolant pump, electrically powered at low cooling load and belt-driven when high cooling performance is needed, and a 2-cylinder clutched air compressor, with turbo and EGR systems updated to the new valve timing and new fuel injectors. DAF Components’ 2025 infosheet ties the Miller timing and the clutched air compressor to EU vehicles configured with option 03683, and gives a compression ratio of 19.4 to 1 for MY25 (03683) and 18.5 to 1 for MY24 (03670).

2025: the B100 version

On 7 April 2025 DAF announced that the New Generation DAF XF, XG and XG+ “can now also be delivered with a specially developed PACCAR MX-13 engine”, for both tractors and rigids. The release gives it as “the B100-compatible MX-13 (355 kW/480 pk)” with “specially designed software that takes factors such as the lower calorific value of biodiesel into account”.

North America: EPA 2021, EPA 2024 and CARB low NOx

PACCAR’s two US sheets carry the certification “EPA 2021” and “EPA 2024” and list the same ratings. On 4 June 2024 Peterbilt announced “a new CARB low nitrogen oxide (NOx) compliant PACCAR MX-13 engine” for its Models 579, 567 and 589, which “meets the CARB Omnibus Regulation”. The release describes a larger volume aftertreatment system with “a 48-volt generator located in the flywheel housing, and an electrical heater located in the inlet”, and internal hardware with a larger volume mixer and a longer selective catalytic converter (SCR).

Fuels and emission class

DAF Components’ infosheet and truck-engine page, DAF’s launch release of 2021 and Peterbilt’s CARB release describe the MX-13 as a diesel engine; none of the documents read for this page lists a natural-gas version.

• Diesel and HVO. DAF’s alternative-fuels infosheet says “All DAF vehicles run on HVO”, and its IAA 2024 release that PACCAR MX engines “are fully prepared to operate on HVO biodiesel”. DAF Components’ coach and bus page states that “(Bio) Diesel fuel must comply with EN-590 / EN-15940 / EN-16734 / EN-16709”. HVO, which the alternative-fuels infosheet lists under EN15940, is covered in what is HVO fuel.
• Biodiesel blends. The same infosheet says “all PACCAR MX engines are also suitable for B30”.
• B100. “B100 can only be used in DAF’s with specific MX-13 480 B100 engines”, which the infosheet describes as “mapped and prepared to run on B100”.

DAF Components describes the MX-13 as “The 12.9 litre Euro 6 PACCAR MX-13 engine”; its truck-engine page lists Euro 3, 5 and 6 settings, as above. None of the European documents read names the Euro VI step (A to E) of a given build. The steps from Euro VI A to E and what Euro 7 adds are covered in Euro VI and Euro 7. In the United States the engine is certified to EPA 2021 and EPA 2024 on PACCAR’s sheets, and the CARB low NOx version meets the CARB Omnibus Regulation.

The engine brake that DAF Components lists, an integrated compression release brake, is the kind described in retarders and engine braking.

Beyond trucks and buses

DAF’s release of 7 July 2025 describes the inland cargo vessel Mannheim, 200 metres long, with a diesel-electric powertrain built around five PACCAR MX-13 engines supplied by DAF Components. Each engine, “adapted for marine use by Dutch NPS Driven, drives a generator that powers two electric motors”. The release gives the powertrain’s maximum as 2650 hp (1946 kW).

Trucks and buses on this site with the PACCAR MX-13

Five model pages on this site list the PACCAR MX-13. 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.

Two North American models record their engines in their notes, in the maker’s units. The Kenworth T680 page gives the PACCAR MX-13 as 12.9 l, 405-510 hp and 1,550-1,850 lb-ft on Kenworth’s US page (EPA 2024 on PACCAR’s sheet), 1450-1850 lb-ft on Kenworth Mexicana’s page (Euro VI), and a CARB MX-13 at 455 hp and 1,650 lb-ft or 510 hp and 1,850 lb-ft. The Peterbilt 579 page gives the PACCAR MX-13 as 12.9 l, 405-510 hp and 1,550-1,850 lb-ft (EPA 2024 on PACCAR’s sheet), and the same two CARB ratings.