When buying a used Mercedes-Benz C-Class C350 2011 (204), the most frequently mentioned issue is oil leaks (gaskets and oil cooler). High oil consumption (piston rings/PCV) is also commonly reported.
Engine varies by trim; verify the engine code on the listing.
Listed from most frequently reported, each with its source.
Oil leaks are frequently reported around the oil-water heat exchanger, valve cover gaskets, and seals. While initially slow, if neglected, they can lead to low oil level and risk of engine damage.
Engine Bay
Many OM642 owners report higher than normal oil consumption due to stuck piston rings from carbon buildup, oil separator/PCV issues, or internal leaks causing excessive smoke and more frequent DPF regeneration.
Engine Internal
At high mileage, the timing chain may stretch or tensioners may wear, causing metallic rattling/clicking when cold, abnormal vibrations, and risk of valve timing jump leading to serious engine damage.
Timing Chain
The EGR system and DPF are prone to clogging due to carbon buildup, especially with city driving or little highway use; this leads to frequent regenerations, warning lights, and power loss.
Exhaust Emissions
In many OM642 units, turbochargers (especially variable geometry) can suffer from actuator sticking, excessive play, or damage due to oil contamination or starvation. The exhaust manifold may also crack or lose internal lining pieces.
Turbo
Same trim, different year
We only publish claims we can verify. Cards come from Difetti fault records matched to this vehicle on brand, fuel, engine and generation.