Reliability and common problems · Mercedes-Benz
Mercedes-Benz C-Class reliability and common problems
12 sourced problems for cars built from 2012, generation by generation — what Mercedes-Benz has acknowledged kept apart from what the motoring press reports. Choose the year, fuel and engine size to see the ones for a particular car.
Free · no signup · researched from manufacturer statements and motoring publications
How reliable is the Mercedes-Benz C-Class? What the evidence shows
We don't give the C-Class a reliability score — no public source measures breakdowns, warranty claims or repair costs across every model, so a single number would be invented. This is what we can source for cars built from 2012.
- Acknowledged by Mercedes-Benz
- 0
- Warranty extensions, goodwill schemes and service actions in our research
- Reported by the press
- 12
- Each by two or more independent publishers
By generation
- C-Class (W206) (2021 on)0 acknowledged · 1 reported
- C-Class (W205, saloon, estate, coupe, cabriolet) (2014–2021)0 acknowledged · 7 reported
- C-Class (W204) (2007–2014)0 acknowledged · 6 reported
Newer generations have had less time on the road for problems to show, so a short list is not a clean bill of health.
Where these come from: our research is built from manufacturer statements and motoring publications, most of them British. A warranty extension or goodwill scheme described here may have been offered in another country only — ask a dealer here whether it applies to your car.
C-Class (W206) (2021 on)
Acknowledged by the manufacturer
Problems the maker has admitted — through an extended warranty, a compensation scheme, a service action or a statement.
None that we hold for this model.
Reported by owners and the motoring press
Problems at least two independent publishers report on this model, that the maker has not acknowledged. They describe the model, not this car — many cars never have them.
- Reported by 2 publishersEngine
If it has the OM642 3.0 V6 diesel (350 CDI / 350 d / 3.0 CDI vans): 3.0 V6 diesel: oil leak from hardened oil-cooler seals
The 3.0 V6 diesel's oil cooler sits in the middle of the V, and its rubber seals can harden with heat and let oil out. The leak shows as oil under the car or at the bottom of the gearbox bell housing and is often misdiagnosed as a rear crankshaft seal. The repair means removing the turbo and intake parts to reach the cooler, so it is labour-heavy. Mercedes moved to an upgraded seal material around 2010, which made the leak less common but did not end it.
Applies to: Cars and vans with the OM642 3.0 V6 diesel (E/S/M/GL/GLE/GLS/CLS/G 350 CDI or 350 d, Sprinter and Viano 3.0 CDI); less common on engines built after about 2010
5 sources
- ID Parts (Mercedes diesel parts specialist) — Mercedes Oil Cooler Seal Leak on 3.0L V6 Engines
- ID Parts (Mercedes diesel parts specialist) — Mercedes Oil Cooler Seal Leak on 3.0L V6 Engines
- ID Parts (Mercedes diesel parts specialist) — Mercedes Oil Cooler Seal Leak on 3.0L V6 Engines
- O.G.S. Mechanics (UK independent specialist) — Mercedes M-Class diesel engine oil leak
- O.G.S. Mechanics (UK independent specialist) — Mercedes M-Class diesel engine oil leak
C-Class (W205, saloon, estate, coupe, cabriolet) (2014–2021)
Acknowledged by the manufacturer
Problems the maker has admitted — through an extended warranty, a compensation scheme, a service action or a statement.
None that we hold for this model.
Reported by owners and the motoring press
Problems at least two independent publishers report on this model, that the maker has not acknowledged. They describe the model, not this car — many cars never have them.
- Reported by 2 publishersEmissions, DPF & AdBlue
Diesel: DPF, NOx sensor and AdBlue faults
Diesel C-Classes of this generation are reported to suffer faults in the emissions system: a blocked diesel particulate filter (DPF), failed NOx or other exhaust-gas sensors, and AdBlue system faults. Short-trip use makes the DPF side worse. Owners report the sensors failing at relatively low mileage, and replacing them is not cheap.
Applies to: C-Class W205 (2014–2021) with a diesel engine
- Reported by 2 publishersFuel system
Petrol smell from a loose or porous fuel line
A smell of petrol on a petrol C-Class of this generation is usually a loose or porous fuel line from the fuel pump. It is often worse from cold. It is a relatively cheap fix, but should be put right.
Applies to: C-Class W205 (2014–2021) with a petrol engine
- Reported by 3 publishersInterior
Creaks from the dashboard, sunroof and door seals
Owners of this C-Class report creaks and rattles from the dashboard, roof lining, sunroof and door seals or door cards. It is an annoyance rather than a mechanical fault, but it is worth listening for on a test drive over rough roads.
Applies to: C-Class W205 (2014–2021), all engines
- Reported by 3 publishersScreen, sat-nav & audio
Infotainment: slow, freezing screen and faulty touchpad
The infotainment on this C-Class draws complaints: the entry Audio 20 navigation is described as very slow, the COMAND system can freeze, and the touchpad and centre-console switches can play up. Software and map updates help. Check every function on a test drive.
Applies to: C-Class W205 (2014–2021), all engines
The picker doesn't record which infotainment system (Audio 20 or COMAND) a car has, so this shows for every W205 C-Class.
- Reported by 2 publishersEngine
Plastic air-intake parts can crack with age
Plastic parts of the air intake on this C-Class can crack as they age, which can upset idle and running. Autocar names the plastic inlet manifold, alongside a leaking plastic fuel-filter housing, in its notes on the 220d diesel. Parkers lists cracked plastic air inlets and failing crankcase-ventilation valves among the W205's engine weak points.
Applies to: C-Class W205 (2014–2021); Autocar ties the inlet-manifold crack to the 220d diesel
- Reported by 2 publishersCooling
If it has the M274 1.6 / 2.0 turbo petrol: Petrol: early thermostat failure, labour-heavy to replace
Some 1.6 and 2.0 turbo petrol C-Classes of this generation have had the thermostat fail early. The engine may run cool or the temperature gauge may behave oddly. The part itself is cheap, but it is hard to reach, so the labour bill can be large.
Applies to: C-Class W205 (2014–2021) with the 1.6 or 2.0 turbo petrol engine
- Reported by 2 publishersEngine
If it has the OM642 3.0 V6 diesel (350 CDI / 350 d / 3.0 CDI vans): 3.0 V6 diesel: oil leak from hardened oil-cooler seals
The 3.0 V6 diesel's oil cooler sits in the middle of the V, and its rubber seals can harden with heat and let oil out. The leak shows as oil under the car or at the bottom of the gearbox bell housing and is often misdiagnosed as a rear crankshaft seal. The repair means removing the turbo and intake parts to reach the cooler, so it is labour-heavy. Mercedes moved to an upgraded seal material around 2010, which made the leak less common but did not end it.
Applies to: Cars and vans with the OM642 3.0 V6 diesel (E/S/M/GL/GLE/GLS/CLS/G 350 CDI or 350 d, Sprinter and Viano 3.0 CDI); less common on engines built after about 2010
5 sources
- ID Parts (Mercedes diesel parts specialist) — Mercedes Oil Cooler Seal Leak on 3.0L V6 Engines
- ID Parts (Mercedes diesel parts specialist) — Mercedes Oil Cooler Seal Leak on 3.0L V6 Engines
- ID Parts (Mercedes diesel parts specialist) — Mercedes Oil Cooler Seal Leak on 3.0L V6 Engines
- O.G.S. Mechanics (UK independent specialist) — Mercedes M-Class diesel engine oil leak
- O.G.S. Mechanics (UK independent specialist) — Mercedes M-Class diesel engine oil leak
C-Class (W204) (2007–2014)
Acknowledged by the manufacturer
Problems the maker has admitted — through an extended warranty, a compensation scheme, a service action or a statement.
None that we hold for this model.
Reported by owners and the motoring press
Problems at least two independent publishers report on this model, that the maker has not acknowledged. They describe the model, not this car — many cars never have them.
- Reported by 2 publishersGearbox
Automatic: harsh shifts or a clunk from a faulty gearbox valve
On cars with the seven-speed 7G-Tronic automatic, harsh or jerky gearchanges or a clunk are usually caused by a faulty valve in the gearbox. Left alone it can damage the gearbox, and putting it right can cost thousands.
Applies to: C-Class W204 (2007–2014) with the seven-speed 7G-Tronic automatic
The make, model and year can't tell us the gearbox, so this shows for every W204 — it only applies to cars with the seven-speed automatic (some earlier cars had a five-speed automatic, and manuals were sold too).
- Reported by 2 publishersElectrics
Moisture and condensation getting into the headlamps
Water and condensation can get into the headlamps. Lamps fitted after the facelift are less prone to it, but it is worth checking any car.
Applies to: C-Class W204 (2007–2014), mainly before the facelift
Parkers names the xenon headlamps; the picker doesn't record which headlamps are fitted.
- Reported by 2 publishersBody & corrosion
Rust around the boot lid
Corrosion can appear around the boot, most often along the edge of the boot lid near the release handle, and is becoming more common as these cars age.
Applies to: C-Class W204 (2007–2014)
- Reported by 2 publishersBody & corrosion
Noisy power-folding door mirrors
The power-folding door mirrors can become noisy. Sometimes a cheap internal part cures it, but a complete mirror is expensive to replace.
Applies to: C-Class W204 (2007–2014) with power-folding mirrors
Only cars with power-folding mirrors; the picker doesn't record the option.
- Reported by 2 publishersInterior
Leather and part-leather seats wear badly
The interior does not wear well where leather is fitted, and the seats, particularly with part-leather trim, can burst their stitching around the seat bases.
Applies to: C-Class W204 (2007–2014) with leather or part-leather trim
Upholstery depends on trim and options; the picker doesn't record it.
- Reported by 2 publishersEngine
If it has the OM642 3.0 V6 diesel (350 CDI / 350 d / 3.0 CDI vans): 3.0 V6 diesel: oil leak from hardened oil-cooler seals
The 3.0 V6 diesel's oil cooler sits in the middle of the V, and its rubber seals can harden with heat and let oil out. The leak shows as oil under the car or at the bottom of the gearbox bell housing and is often misdiagnosed as a rear crankshaft seal. The repair means removing the turbo and intake parts to reach the cooler, so it is labour-heavy. Mercedes moved to an upgraded seal material around 2010, which made the leak less common but did not end it.
Applies to: Cars and vans with the OM642 3.0 V6 diesel (E/S/M/GL/GLE/GLS/CLS/G 350 CDI or 350 d, Sprinter and Viano 3.0 CDI); less common on engines built after about 2010
5 sources
- ID Parts (Mercedes diesel parts specialist) — Mercedes Oil Cooler Seal Leak on 3.0L V6 Engines
- ID Parts (Mercedes diesel parts specialist) — Mercedes Oil Cooler Seal Leak on 3.0L V6 Engines
- ID Parts (Mercedes diesel parts specialist) — Mercedes Oil Cooler Seal Leak on 3.0L V6 Engines
- O.G.S. Mechanics (UK independent specialist) — Mercedes M-Class diesel engine oil leak
- O.G.S. Mechanics (UK independent specialist) — Mercedes M-Class diesel engine oil leak
These describe the model, not one car. Plenty of cars never have the problems their model is known for. Every problem links to its sources; a reported problem needs two independent publishers before we list it.
Recalls aren't listed here. A franchised dealer can tell you from the VIN whether a recall is open on a particular car.
Common questions
Is the Mercedes-Benz C-Class reliable?
We don't score reliability: no public source records breakdowns, warranty claims or repair costs across every model, so a single rating would be guesswork. What we hold for Mercedes-Benz C-Class cars built from 2012: 0 problems Mercedes-Benz has acknowledged, through a warranty extension, goodwill scheme or service action, and 12 reported by at least two independent publishers — listed above by generation, each with its sources. Which matter depends on the generation and engine, and on whether the work has been done, which a service history check shows.
What are the most common Mercedes-Benz C-Class problems?
For cars built from 2012, the problems at least two independent publishers report include: 3.0 V6 diesel: oil leak from hardened oil-cooler seals; Diesel: DPF, NOx sensor and AdBlue faults; Petrol smell from a loose or porous fuel line; Creaks from the dashboard, sunroof and door seals; Infotainment: slow, freezing screen and faulty touchpad. Which apply depends on the generation and engine — they are listed generation by generation above, each with its sources.
Has Mercedes-Benz acknowledged problems with the C-Class?
We haven't found a warranty extension, goodwill scheme or service action in which Mercedes-Benz acknowledged a problem on this model. The reported problems above come from the motoring press.
Does every C-Class have these problems?
No. These describe the model; many cars never have them, and a well-maintained car is less likely to. Whether a known problem was fixed is what a service history shows: our check returns the manufacturer's dealer records by VIN, and there's no charge if we find nothing.
Has this car had the work done?
A known problem matters far less on a car whose dealer records show it was fixed. A service history check returns the manufacturer's own dealership records for a specific car, found by its VIN — what was done, when and at what mileage — and there's no charge if we find nothing.
Check a car's service history