Mercedes-Benz OM642 engine

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Mercedes-Benz OM642 engine
OM 642 air box.jpg
ManufacturerDaimler AG
Configuration72° V6
Displacement3.0 L; 182.3 cu in (2,987 cc)
Cylinder bore83 mm (3.27 in)
Piston stroke92 mm (3.62 in)
Block materialAluminium
Head materialAluminium
ValvetrainDOHC 4 valves x cyl.
Compression ratio18.0:1
TurbochargerVariable nozzle Garrett GT2056VK
Fuel systemCommon rail direct injection
Fuel typeDiesel
Cooling systemWater cooled
Power outputEuropean models: 195 kW (265 PS; 261 hp). US vehicles: 157 kW (213 PS; 211 hp). Mercedes/Dodge Sprinter: 140 kW (190 PS; 188 hp).
Torque outputEuropean models: 620 N⋅m (457 lb⋅ft). US vehicles: 540 N⋅m (398 lb⋅ft). Mercedes/Dodge Sprinter: 440 N⋅m (325 lb⋅ft).
Dry weight208 kg (459 lb)
PredecessorMercedes-Benz OM648 engine
SuccessorMercedes-Benz OM656 engine
VM A630 (VM Motori)

The Mercedes-Benz OM642 engine is a 3.0 litres (2,987 cc), 24-valve, aluminium/aluminium block and heads diesel 72° V6 engine manufactured by the Mercedes-Benz division of Daimler AG as a replacement for the Mercedes straight-5 and straight-6 cylinder engines.[1]

The engine features common rail Direct injection and a variable nozzle turbocharger. The injection system operates at 1,600 bar (23,000 psi), while the compression ratio is 18.0:1.[1] The engine features a counter-rotating balance shaft mounted between the cylinder banks to cancel the vibrations inherent to the 72 degree V6 design, and the crankpins are offset by 48 degrees to achieve even 120 degree firing intervals. In some heavy vehicle applications, Mercedes' BlueTec AdBlue urea injection is utilised for NOx reduction.[2] In lighter vehicle applications, a NOx storage catalyst captures nitrous oxides, which are periodically purged (decomposed) by running the engine slightly rich. A particulate filter lowers soot, making this engine ULEV certified.[2][3] Engine mass is 208 kg (459 lb). Power output is 165 kW (224 PS; 221 hp) and 510 N⋅m (376 lb⋅ft) of torque.[1] For the 2007 model year, torque is raised to 540 N⋅m (398 lb⋅ft).

At the beginning of summer 2017 the engine, together with Mercedes-Benz OM651 was under investigation by the Federal Motor Transport Authority in respect of the alleged emissions cheating scandal wherein the laboratory emissions testing produced a different amount of diesel exhaust fluid usage and lower emissions than in real world operating scenarios. [4]


Vehicles using this engine include:

1 EMEA market 2 NAFTA market

Intake System[edit]

Air is drawn into the engine through two air filters located above each cylinder head. The amount of the air is measured by two hot film mass air flow sensors B2/6&7. On Sprinter models, a single air filter housing is mounted upon brackets on top of the engine.

OM642 VGT full boost position

The variable geometry Turbine is actuated via a linkage connecting the controller to vanes inside the Turbine housing. In the full-boost position, air is allowed to pass over the Turbine impeller. In the no boost position the vanes block exhaust gasses from acting on the impeller and route them down the exhaust pipe.

OM642 VGT no boost position

See also[edit]


  1. ^ a b c "05_kompact_en.doc" (PDF). Retrieved 2009-02-13.
  2. ^ a b Consumer Reports: What is BlueTec? Archived 2009-06-06 at the Wayback Machine
  3. ^ "Motive Magazine ULEV certification, Diesel Car Bomb BlueTec". Archived from the original on 2008-10-25. Retrieved 2009-04-18.
  4. ^ Abgas-Skandal: KBA findet angeblich deutliche Hinweise auf illegale Abschalteinrichtungen in Mercedes-Dieselautos, heise, 2017-07-14