Mercedes-Benz C 180d
Renault-based small diesel, new generation. Economical with SCR catalyst, but still with little power reserve. Automatic only.
Smallest Diesel, Wrong Car
90 kW four-cylinder CDI in the W205 — economical, but at odds with the premium pretension. For company-car kilometres, not for enjoyment.
Engine Weaknesses 5
Like its Renault counterpart, the OM608 uses a timing belt. Prescribed change every 120,000 km or 6 years -- frequently forgotten as Mercedes buyers are accustomed to timing chains.
Symptoms: No warning on snap -- sudden engine failure and severe engine damage
The OM608 (Renault K9K base) uses a timing belt. Mercedes specifies 200,000 km change interval; Renault prescribes 120,000 km for the same engine. A snap causes immediate total damage on this interference engine.
Symptoms: No noticeable warning before snap; beforehand: faint squealing, occasionally starting difficulties
The Renault-based OM608 1.5 CDI sometimes shows increased oil consumption from early on due to a leaking turbocharger shaft seal. Oil mist in the intake tract behind the turbo.
Symptoms: Dropping oil level, oil mist or blue smoke from exhaust, oil in air filter housing behind turbo
As a Renault K9K derivative, the OM608 shares the known EGR valve weakness. With frequent short-trip use, soot particles accumulate, the valve seizes and triggers limp mode.
Symptoms: Engine warning light, power loss, limp mode at around 3000 rpm, increased fuel consumption
With predominantly short-trip use, the OM608 is prone to DPF blockage. Regeneration intervals shorten until active regeneration is no longer sufficient and the filter must be manually regenerated or replaced.
Symptoms: DPF warning light, frequent active regeneration, fuel dilution in oil, power loss
Vehicle Weaknesses 7
Longitudinal members, jack-point attachment holes and rear axle subframe rust through. MB offers goodwill replacement.
Polycarbonate blind cover of the panoramic roof incorrectly bonded. When opening, the blind can come loose. Recalled by MB.
Ball joints on the wheel-side wishbone and rubber-metal bushes wear. New suspension geometry makes repairs more involved.
Some W205 models discharge the battery unusually quickly during extended parking. Cause: elevated quiescent current draw from control units.
The W205 shows above-average front axle issues from the second MOT onwards according to TÜV statistics. Worn control arms and drop links are the main causes.
W205 A/C fails with 'Air conditioning off' without a fault code in the onboard computer. Often the compressor or A/C control unit is defective.
Panoramic roof on the W205 creaks when opening and closing. Guide linkage can bend and jam the roof. Repair often requires complete removal.