Mercedes-Benz OM642
3.0 L · V6 · turbocharged · diesel · 2005–present
Also known as: 3.0 cdi, 320 cdi, 350 cdi, v6 cdi, om642 de 30 la
Mercedes-Benz's V6 diesel, badged 320 CDI and later 350 CDI, and fitted to almost everything the company sold with a diesel option — saloons, SUVs, the Sprinter and the Vito. Common-rail, 72° V6, all-aluminium.
The fault it is known for is the oil cooler seals, which sit in the valley between the cylinder banks under the intake. They harden and leak, oil appears at the back of the engine, and because the leak is above the bellhousing it is routinely misread as a rear main seal or a gearbox problem. The repair is labour-heavy because the intake assembly has to come off; the part itself is trivial.
The second theme is the intake tract: swirl flaps and their linkage, and heavy carbon build-up in the manifold on short-journey cars. Both produce airflow and performance complaints with no single obvious component at fault. On higher-mileage examples the turbocharger's variable-geometry mechanism sticks, which reads as a boost fault and often frees with cleaning rather than replacement.
Cars fitted with this engine
20 generations, across 3 makes. From the authored catalogue — an absent car means the catalogue has not reached it, not that the engine was never fitted.
Chrysler
Mercedes-Benz
- G-Class W463 1990–2018
- C-Class W203 2000–2007
- E-Class W211 2002–2009
- Vito W639 2003–2014
- CLS W219 2004–2010
- S-Class W221 2005–2013
- GLE W164 2005–2011
- Sprinter W906 2006–2018
- GLS X164 2006–2012
- C-Class W204 2007–2014
- E-Class W212 2009–2016
- GLE W166 2011–2019
- CLS C218 and C257 2011–2023
- GLS X166 2012–2019
- S-Class W222 2013–2020
- GLC X253 2015–2022
- E-Class W213 2016–2023
- Sprinter W907 2018–present
Information, not instruction
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