Elegant two-door coupe with timeless Mercedes style
Produced from 1997 to 2009 across two generations, the CLK sits between C-Class and E-Class as Mercedes' mid-size coupe and cabriolet. W208 (1997-2002) models now start from £1,500, while the better W209 (2003-2009) ranges from £3,000-£12,000 for clean examples. The CLK 55 AMG with its 5.4-litre V8 commands £5,000-£10,000 depending on condition. An emerging modern classic with strong enthusiast following in the UK.
We track 5 known issues across the Mercedes-Benz CLK range, with 5 classified as significant. Knowing which variants and configurations to approach with caution can save you from expensive surprises after purchase.
Found a Mercedes-Benz CLK? Enter the reg to see which of our 5 known issues apply to that exact car, plus full MOT history and mileage checks.
C208 (1997–2003) — Engine options included the 2.0 Petrol, 2.3 Petrol, 3.2 V6 Petrol, 4.3 V8 Petrol, 5.4 V8 AMG. We track 4 known issues on this generation, with 4 classified as significant. The most significant concern is Suspension component corrosion and damage (£200–£800 to address).
C209 (2002–2010) — Petrol options included the 1.8 Kompressor, 2.6 Petrol, 3.0 V6 Petrol, 3.2 V6 Petrol, 3.5 V6 Petrol, 3.5 AMG, 5.0 V8 Petrol, 5.4 V8 AMG, with 2.1 CDI, 2.7 CDI, 3.0 CDI on the diesel side. We track 5 known issues on this generation, with 5 classified as significant. The most significant concern is Suspension component corrosion and damage (£200–£800 to address).
Mercedes CLK models show abnormally high rates of suspension component failure due to corrosion and structural damage. MOT data shows this model fails at 822.2x the national fleet average for suspension damage across all engine variants. The multi-link rear suspension uses steel components that are prone to corrosion, particularly the lower control arms and anti-roll bar links. Front suspension strut top mounts and lower ball joints also fail at elevated rates.
Corroded or damaged suspension components compromise handling and safety. In severe cases, component failure can cause loss of control. Worn ball joints can separate completely, causing wheel misalignment and potential accident. The car should be inspected immediately if suspension noise or handling issues develop.
Listen for knocking, clunking or rattling over bumps during the test drive. Inspect the underside for corroded or cracked suspension components. Check the MOT history for suspension-related advisories, which often predict future failures.
CLK models suffer from premature wear of steering ball joints, with MOT failure rates 98x higher than the national average. The issue affects track rod ends and steering linkage components across all engine variants. Wear is accelerated by the car's weight distribution and the design of the steering geometry, particularly on higher-mileage examples.
Worn ball joints cause imprecise steering and can fail completely, leading to loss of steering control. Excessive play reduces directional stability and increases tyre wear. Complete joint failure can cause wheel misalignment and potential accident.
During the test drive, check the steering for excessive play, vibration or pulling to one side. Listen for groaning or whining when turning the wheel at low speed. Power steering fluid level and condition should be checked on hydraulic systems.
CLK models show exceptionally high rates of flexible brake hose failure, with MOT data indicating 64x higher failure rates than the fleet average. The rubber brake hoses deteriorate and can become damaged, chafed, or twisted. This issue affects all variants and can occur at any mileage, including low-mileage examples.
Failed brake hoses can cause brake fluid loss, leading to reduced braking effectiveness or complete brake failure. Bulging hoses can burst under pressure, particularly during emergency braking. This is a serious safety issue that requires immediate attention.
Check brake disc condition for lipping or scoring. Test braking at moderate speed for pulling to one side or vibration through the steering wheel. Review MOT advisories for brake-related items.
CLK models suffer from premature wheel bearing wear, with MOT failure rates 29x higher than the national fleet average. The issue affects both front and rear bearings and can occur at relatively low mileages. The bearings are integrated hub units that cannot be serviced and must be replaced as complete assemblies.
Worn wheel bearings cause noise, vibration, and can affect ABS sensor operation. In extreme cases, bearing failure can cause wheel wobble and loss of control. Complete failure can result in wheel separation from the vehicle.
Listen for knocking, clunking or rattling over bumps during the test drive. Inspect the underside for corroded or cracked suspension components. Check the MOT history for suspension-related advisories, which often predict future failures.
The 2.7 CDI and 3.0 CDI engines are particularly affected. Short journey patterns and urban driving prevent proper DPF regeneration, leading to progressive blockage and eventual failure.
A blocked DPF causes reduced engine power, increased fuel consumption, and eventually complete blockage requiring expensive replacement. DPF replacement costs £2000-£4000. Continued driving with a blocked filter can damage other engine components including the turbocharger.
Ask about the car's typical usage — short urban journeys prevent DPF regeneration. Check for DPF warning lights and ask about any previous regeneration issues. A forced regeneration at a garage costs far less than a DPF replacement.
For the full breakdown of all 5 tracked issues with repair costs, see the Mercedes-Benz CLK common problems page.
Based on 174k real DVSA MOT tests, the Mercedes-Benz CLK fails more often than average on several items. The biggest outlier is coil springs broken at 405x the fleet average, followed by steering rack wear (244x).
When viewing a specific car, check its MOT history for recurring advisories in these categories. See the full Mercedes-Benz CLK MOT failure breakdown for data at every mileage point.
Routine servicing (oil and filter change every 12k miles) typically costs £80–£120 at an independent garage.
The bigger-ticket items to budget for include automatic transmission fluid (£200–£300).
See the full Mercedes-Benz CLK service schedule for every interval and cost breakdown.
The Mercedes-Benz CLK is a solid choice on the used market, though not without its quirks. The issues we track are well-understood and largely avoidable if you know what to look for. A thorough inspection and complete service history go a long way. 2005-2009 W209 facelift is the best choice — the post-2004 cars resolved the Valeo radiator issues, and the CLK 280 with 7G-TRONIC gearbox offers the best balance of performance and reliability. Avoid pre-2003 W208 models due to age-related electrical decay. For AMG buyers, later CLK 55 AMG (2004-2006) cars are preferable to early examples.
Before committing, check the car's full MOT history, verify the service record is complete, and if possible arrange a specialist inspection. Enter any registration into our free report to see the complete picture.
Get Car Wise maintains a database of known mechanical issues for every popular car on UK roads, tracking the faults that owners, specialists and DVSA data reveal.
When you run a report on a specific Mercedes-Benz CLK, we cross-reference the exact variant, engine and age against our database of 5 known issues. Combined with full MOT history analysis, mileage verification and DVLA data, you get a complete picture before viewing.
Enter the registration for MOT history, mileage verification, known faults for that exact variant, and a Get Car Wise Score.
This guide was compiled from independent expert reviews, DVSA MOT data, specialist workshops and our own database of 5 known Mercedes-Benz CLK issues. We are not affiliated with any source listed.