C-Class W204
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Which Mercedes Benz C-Class W204 engine is the most reliable? See common problems, reviews and reliability verdicts across generations and engines.
Frequently asked questions
Which Mercedes Benz C-Class W204 engine is the most reliable?
E200 / E220 CDI 2.2 (OM646) — Reliable verdict. The 4-cylinder CDI — noisy but close to invincible, the high-mileage hero of the W211 range, good for 400,000 km with care. 'Reliable' is well earned, but it has two genuine design weaknesses to check: the plastic intake swirl flaps break up with age and, if a piece is drawn into a cylinder, can wreck the engine (many owners delete or fit metal flaps); and the injector copper sealing washers harden and leak combustion gases ('black death' carbon around the injector base), which clogs injectors and makes long-untouched ones seize and hard to extract. Service those and watch for oil leaks and you have one of the most durable Mercedes diesels.
Which Mercedes Benz C-Class W204 engines should you avoid?
Engines with the weakest reliability verdicts: C180 / C200 / C250 CGI 1.8 (M271).
What are the most common Mercedes Benz C-Class W204 problems?
The most commonly reported problems across all Mercedes Benz C-Class W204 generations and engines: Piezo injector failure (early cars), Cylinder head bolt corrosion/failure, Intake camshaft & lifter wear, Intake swirl flap failure, Balance shaft gear wear (early serials).