All generations and engines together · 4,584 MOT tests in the 2025 data · typical mileage at age 7: 51k
Not enough recent tests to rate this coupé or convertible. Watch brakes and suspension. Not enough recent MOT data to call this one yet.
Owner folklore from forums and the motoring press, with how well each report stands up. Most of it never shows up in an MOT, which is why this section exists at all.
On CLC 180 and 200 Kompressor petrol cars the M271 engine's balance-shaft chain tensioner wears and lets the timing chain rattle, worst on a cold start. Left alone it can let the chain jump and wreck the engine. Mercedes revised the tensioner and balance-shaft parts and ran a recall campaign covering the fault on M271 engines, with UK cars eligible for the same updated parts through a dealer. Expect roughly £600-1,500 for a proper tensioner and balance-shaft repair if caught early, considerably more if the chain has already jumped.
Cars fitted with Mercedes' 5-speed 722.6 automatic can develop harsh or delayed shifts, a limp-home mode, or a gearbox warning light as the internal wiring loom (the conductor plate) inside the valve body degrades with age and heat. It's a well known weak point across this whole generation of Mercedes automatics, not unique to the CLC. Repair means dropping the pan and replacing the conductor plate and harness, typically £400-900 at an independent specialist rather than a full rebuild. Manual cars aren't affected.
The CLC shares its bodyshell with the W203 C-Class, a car with a well earned reputation for rust, and owners still report bubbling around the rear wheel arches, sills and exhaust hangers on cars from this later, supposedly better-protected production run. Some owners insist the facelift-era cars are much improved and it's just stone chips and bad past repairs; others see the same rot once the car passes 10-15 years old. A proper arch or sill repair runs roughly £300-800 per side depending on how far the corrosion has spread.
On the 220 CDI, worn glow plugs bring a hard, smoky cold start and a dashboard warning light, while the swirl flaps in the intake manifold can stick or snap off with age, causing rough idle, hesitation or a limp-home mode. Both are wear items on higher-mileage OM646-family diesels rather than manufacturer-acknowledged defects. Budget roughly £150-300 for a set of glow plugs and £300-600 for swirl flap repairs; ignoring a rattly or hesitant diesel risks debris getting drawn into the engine.
The front and rear Signal Acquisition Modules (SAM units) that run the CLC's lighting, central locking, wipers and indicators are known to develop dry joints or water ingress with age, producing seemingly unrelated warning lights and electrical faults that come and go. It isn't officially acknowledged by Mercedes as a defect, but it comes up often enough across the wider W203/W204-era range to take seriously on a used CLC. Repair ranges from a re-soldered board at an auto-electrician for under £150 to £400-plus for a full replacement module.
Owners of the CLC, sold as a sportier-looking coupe, commonly report front discs and pads wearing faster than on the equivalent saloon, plus calipers and handbrake mechanisms that stick after the car sits unused for a few days, both fairly ordinary wear complaints rather than a hidden manufacturing fault. This lines up with the measured MOT data, where brakes are the standout failure category for this segment; the everyday explanation, a heavier car driven with enthusiasm plus short journeys letting calipers seize, fits that number better than any single design flaw.
Ranked from this model’s own MOT record, then from what owners report.
Saveable checklistThe physical checks its own defect data says are worth your time, most telling first.
These judge the seller’s upkeep rather than the model, and they are where the haggling money is.
Drawn from the reports above rather than the MOT data. These are the model-specific ones.
Computed from DVSA MOT results, all of Great Britain, 2025. Nothing here is opinion.
Share of tests where each item was recorded. The dark tick is the class average across all tracked models; bars are scaled within each group.
The rows that judge the model rather than its keeper. 4,578 tests in this band.
Tyres, pads and stone chips say more about how the car was driven and maintained than about how it was built.
Same segment (Coupés, convertibles & GT), best MOT record first. Compare before you shortlist.