Oil cooler seals (engine valley)
usually 120,000–220,000 km · High risk
Signs: Oil leak at the back of the engine / bellhousing
Fix: Reseal the oil cooler (intake off)
€1,000–2,000
Engine: common problems, timing drive and oil
3.0 CDI V6 (Mercedes OM642)
Diesel · 2,987 cm³ · 140–190 kW
21
model generations
4
known faults
394,000
new cars in the EU (2010–2025)
Enter your VIN and mileage and get a plan built for your exact engine and gearbox.
Fuel: Diesel. Timing drive: chain.
In our database this engine is fitted to 21 model generations, among them: Mercedes-Benz ML / GLE (W166), Mercedes-Benz E-Class (W212), Mercedes-Benz CLS (C218), Mercedes-Benz S-Class (W222), Mercedes-Benz GL / GLS (X166), Mercedes-Benz ML (W164) and 15 more.
The most expensive known risk is timing chain guides (early engines): it usually appears at 150,000–250,000 km and costs €1,500–3,000 to fix.
Key facts
| Fuel | Diesel |
|---|---|
| Displacement | 2,987 cm³ |
| Power | 140–190 kW |
| Years | 2005–2018 |
| Timing drive | Chain |
| Oil | 5W-30 · MB 229.51 · ~8.0 L · every 15,000 km |
| Engine codes | OM642 |
Known engine faults
Faults that belong to the engine itself. They apply to every model with this engine, and each model has its own extra faults on its model page.
Intake swirl flaps / actuator
usually 120,000–220,000 km · Medium risk
Signs: Engine light, limp mode
Fix: Replace manifold or actuator
€600–1,500
EGR / DPF
usually 150,000–250,000 km · Medium risk
Signs: Limp mode
Fix: Clean or replace
€400–1,800
Timing chain guides (early engines)
usually 150,000–250,000 km · Medium risk
model years 2005–2010 only
Signs: Rattle
Fix: Replace guides and chain
€1,500–3,000
Engine-related service
Intervals and typical prices, using the Mercedes-Benz C-Class (W204) as an example. The app gives the exact plan for your car.
| Item | Interval | Typical price |
|---|---|---|
| DPF health check (soot / ash load)Emissions | every 20,000 km | €0–60 |
| Engine oil + oil filterEngine | every 15,000 km or every 12 months | €70–150 |
| Air filterEngine | every 30,000 km or every 24 months | €15–45 |
| Fuel filterFuel | every 30,000 km or every 24 months | €40–110 |
| Glow plugsEngine | every 100,000 km | €120–300 |
| Auxiliary (serpentine) beltEngine | every 120,000 km | €70–180 |
| Coolant replacementCooling | every 150,000 km or every 96 months | €70–150 |
| Timing chain inspection (listen on cold start)Engine | every 150,000 km | €0–120 |
Models with this engine
Model generations this engine is fitted to.
Mercedes-Benz C-Class (W203) 2000–2007Mercedes-Benz C-Class (W204) 2007–2014Mercedes-Benz CLK (C209) 2002–2010Mercedes-Benz CLS (C218) 2011–2018Mercedes-Benz CLS (C219) 2004–2010Mercedes-Benz E-Class (W211) 2002–2009Mercedes-Benz E-Class (W212) 2009–2016Mercedes-Benz E-Class (W213) 2016–2023Mercedes-Benz G-Class (W463) 1990–Mercedes-Benz GL (X164) 2006–2012Mercedes-Benz GL / GLS (X166) 2012–2019Mercedes-Benz GLK (X204) 2008–2015Mercedes-Benz ML (W164) 2005–2011Mercedes-Benz ML / GLE (W166) 2011–2019Mercedes-Benz R-Class (W251) 2005–2013Mercedes-Benz S-Class (W221) 2005–2013Mercedes-Benz S-Class (W222) 2013–2020Mercedes-Benz Sprinter (906) 2006–2018Mercedes-Benz Sprinter (907 / 910) 2018–Mercedes-Benz Vito (W639) 2003–2014Mercedes-Benz X-Class 2017–2020
Common questions
Does the 3.0 CDI V6 (Mercedes OM642) engine have a timing chain or a timing belt?
Chain.
What oil does the 3.0 CDI V6 (Mercedes OM642) engine take?
5W-30 · MB 229.51 · ~8.0 L · every 15,000 km.
What are the known problems with the 3.0 CDI V6 (Mercedes OM642) engine?
The faults with the highest risk: oil cooler seals (engine valley) (120,000–220,000 km, €1,000–2,000); timing chain guides (early engines) (150,000–250,000 km, €1,500–3,000); EGR / DPF (150,000–250,000 km, €400–1,800); intake swirl flaps / actuator (120,000–220,000 km, €600–1,500).
Which cars have the 3.0 CDI V6 (Mercedes OM642) engine?
Mercedes-Benz ML / GLE (W166), Mercedes-Benz E-Class (W212), Mercedes-Benz CLS (C218), Mercedes-Benz S-Class (W222), Mercedes-Benz GL / GLS (X166), Mercedes-Benz ML (W164) and 15 more.
Sources and notes
Faults, intervals and prices are indicative and collected from public sources and owner experience; always rely on the service book and a qualified workshop. Test statistics: DVSA – Anonymised MOT tests and results, Open Government Licence v3.0. Dutch tests: RDW Open Data (CC0). Engine versions: EEA, monitoring of CO₂ emissions from new passenger cars (CC BY 4.0, DG CLIMA). Owner complaints: NHTSA ODI (public domain). Recalls: DVSA Vehicle Safety Branch Recalls Database, OGL v3.0. Brand and model names are trademarks of their owners and are used only to describe the vehicles.
Updated 08/10/2026