Mercedes-Benz OM 473 engine: displacement, ratings and dates

The Mercedes-Benz OM 473 is a 15.6-litre in-line six-cylinder diesel engine from Daimler Truck and the 15.6-litre member of its heavy-duty 47X model series. Mercedes-Benz Powertrain lists it among its Euro VI engine systems for trucks with three ratings, from 380 kW to 460 kW, and describes the 15.6-litre variant as having a turbo compound as standard. Daimler Truck’s own releases name it as an engine of the Mercedes-Benz Actros and Arocs; on this site it is one of the engines of the Actros, Actros L and Arocs.

Status as of 26 October 2026. Read that day: Mercedes-Benz Powertrain’s Truck Euro VI engine page, its Truck Euro VI portfolio (dated 09/2025) and its Bus Euro VI portfolio, Daimler Truck’s press kit of 5 September 2018 on the world premiere of the new Actros, and its press releases of 23 September 2020 on the Actros F and Edition 2, of 18 February 2025 on bauma 2025 and of 7 April 2025 on the Arocs Extent. All seven are the maker’s own documents.

Maker, name and layout

The OM 473 is a Daimler Truck engine. It is listed by Mercedes-Benz Powertrain, through which Daimler Truck offers engine systems, transmissions and axles as components, in its Euro VI engine page for trucks and in its truck portfolio.

The name follows the scheme the truck portfolio sets out: OM marks an oil (diesel) engine, then “47 = 47X model series (HD)” and “3 = L6 cylinder engine (15.6 l)”. The same scheme names the other two engines of the series, the OM 470 and the OM 471. The engine page gives the OM 473 as “Arrangement: L6 | Displacement: 15.6 l”; the portfolio writes “Arrangement: In-line 6”.

Both Mercedes-Benz Powertrain documents name a turbo compound for the 15.6-litre engine. The engine page lists a “15.6 litre variant with a standardly turbo compound”, and the truck portfolio a “15.6-litre variant with turbo compound”. Neither document gives further detail of that stage; how a turbocompound turbine returns exhaust energy to the crankshaft is set out in turbocompound engines.

For the heavy-duty series as a whole, Mercedes-Benz Powertrain lists six-cylinder diesel engines in an in-line arrangement with cooled exhaust gas recirculation, a common rail injection system of up to 2,700 bar with variable injection, a 1-stage turbocharger with asymmetrical turbine geometry, two overhead camshafts with 4-valve technology, additional power take-off options and a “One box” exhaust after-treatment, which the truck portfolio describes as “with SCR and DPF” (how SCR and AdBlue work is covered in SCR and AdBlue explained). It gives engine brakes of up to 480 kW brake power for the heavy-duty series; it gives no separate engine-brake figure for the OM 473. What an engine brake is, and how the law groups it, is set out in retarders and engine braking.

The engine page gives the OM 473’s weight as 1,237 kg (DIN 70020 - GZ) and its dimensions as a length of 1,595 mm, a width of 1,120 mm and a height of 1,220 mm, all “depending on equipment installed”. The truck portfolio gives the same weight.

Euro VI ratings in the Mercedes-Benz Powertrain portfolio

Mercedes-Benz Powertrain’s engine page and its truck portfolio of 09/2025 list three ratings for the OM 473, each with rated power at 1,600 rpm and maximum torque at 1,100 rpm.

Daimler Truck’s press material gives the 460 kW rating with a different horsepower figure: the 2018 press kit describes an Actros 1863 LS with the “OM 473 Euro VI rated at 460 kW/625 hp”, and the 2020 captions write “460 kW (625 hp), 3000 Nm”. Each figure is given here as its document writes it. How kW and hp relate, and what the engine speed beside each figure means, is explained in reading truck power figures.

Mercedes-Benz Powertrain’s Bus Euro VI portfolio lists the OM 470 and OM 471 as the heavy-duty engines in its overview of Euro VI engine systems for buses; the OM 473 is not in that overview.

Fuels and emission class

Mercedes-Benz Powertrain lists the OM 473 among its six-cylinder diesel engines for Euro VI, and every Daimler Truck document read for this page names it with Euro VI. None of the documents lists a gas-fuelled version, and none names HVO or another fuel for the engine.

The photo captions of Daimler Truck’s release of 23 September 2020 give the engine line of an Actros 1863 LS as “OM 473, inline 6, 15.6 l, Euro VI, D”. The documents read for this page do not name a later Euro VI step for the OM 473. The steps from Euro VI A to E and what Euro 7 adds are covered in Euro VI and Euro 7.

Dates in the maker’s documents

None of the documents read for this page dates the engine’s introduction or numbers its generations for the OM 473 alone. The dated maker documents that name the engine are these.

The Arocs Extent release, and the bauma 2025 release before it, word the engine choice of the Arocs Extent as follows: “The truck is powered either by the third-generation Euro VI diesel engine OM 470, OM 471 or the OM 473”. Neither release gives a date for that generation, and the other documents read do not use a generation number for the OM 473.

Trucks and buses on this site with the Mercedes-Benz OM 473

Three model pages on this site list the OM 473 among their engines, all of them trucks; no bus page on the site lists it. The figures below are those recorded on each model’s own page and taken from that page’s source; they are not the engine-level table above.