Used car guide

2003 Mercedes-Benz CLK: common problems and what to check

What gets flagged at MOT on 2003 Mercedes-Benz CLKs, from 2,433 tests in 2025, plus known faults and what to look at before you buy one.

2,433MOT tests in 2025
66%pass first time (all 2003 cars: 59%)
4,700typical miles a year
1.8×the usual rate for ball joint

What stands out

Parts flagged at MOT more often on 2003 Mercedes-Benz CLKs than on all cars registered in 2003.

  • Ball joint1.8× usual
    Mercedes-Benz CLK
    11.1% All 2003 cars
    6.3%

    Failed outright at MOT: 5%, against 2.7% of all 2003 cars. The rest were advisories or minor defects.

    Rough price £60–£150 (one joint) ClickMechanic

    At the viewing: Listen for knocking over bumps and check the rubber boots behind the wheels aren't split.

  • Anti-roll bar5.1× usual
    Mercedes-Benz CLK
    3.6% All 2003 cars
    0.7%

    Failed outright at MOT: 0.1%, against 0.1% of all 2003 cars. The rest were advisories or minor defects.

    Rough price £100–£280 (pair of drop links) Checkatrade

    At the viewing: Drive slowly over bumps and listen for a knock or rattle from the front. Worn anti-roll bar links are a cheap fix.

  • Wheel bearings1.8× usual
    Mercedes-Benz CLK
    6.9% All 2003 cars
    3.8%

    Failed outright at MOT: 0.3%, against 1.3% of all 2003 cars. The rest were advisories or minor defects.

    Rough price £120–£300 (one bearing) ClickMechanic

    At the viewing: Listen for a hum or growl that changes as you steer at speed.

  • Airbag warning light2.6× usual
    Mercedes-Benz CLK
    3.9% All 2003 cars
    1.5%

    Failed outright at MOT: 3.5%, against 1.3% of all 2003 cars. The rest were advisories or minor defects.

    Rough price £10–£80 our estimate

    At the viewing: Ask a friend to check every light while you work the switches: indicators, brake lights, fog lights and reversing lights.

  • Mirrors2× usual
    Mercedes-Benz CLK
    2.6% All 2003 cars
    1.3%

    Failed outright at MOT: 0.5%, against 0.3% of all 2003 cars. The rest were advisories or minor defects.

    Rough price £30–£200 our estimate

    At the viewing: Check both door mirrors adjust and the glass isn't cracked.

Better than most

Rust around suspension or steering mountings: 1% here, against 6.6% of all 2003 cars. Shock absorbers: 3.3% here, against 6.7% of all 2003 cars.

By area

The share of 2003 Mercedes-Benz CLK MOT tests where testers flagged each area, as a fail or an advisory. Rough prices are typical independent-garage costs.

  • Suspension
    45% of testsRough price £120–£400

    At the viewing: Listen for knocks over speed bumps, and look behind each front wheel for a snapped coil spring.

  • Brakes
    39% of testsRough price £150–£350

    At the viewing: Look for a lip on the disc edges and feel for judder or pulling when braking firmly from about 40mph.

  • Lights and electrics
    36% of testsRough price £10–£80

    At the viewing: Ask a friend to check every light, including brake lights and indicators, while you operate them.

  • Tyres
    30% of testsRough price £70–£150

    At the viewing: Check the tread on all four tyres, including the inside edges, and look for cracks or bulges.

  • Oil and fluid leaks
    15% of testsRough price £80–£600

    At the viewing: Look under the engine and on the ground where the car is usually parked for fresh oil or fluid.

  • Exhaust and emissions
    10% of testsRough price £100–£1,200

    At the viewing: Look for black soot in the tailpipe, listen for blowing from the exhaust and check for engine or DPF warning lights.

Looking at a Mercedes-Benz CLK?

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Other years

YearMOT testsMost flagged
20092,745Suspension 46%
20082,454Suspension 48%
20073,399Suspension 50%
20062,832Suspension 47%
20053,419Suspension 48%
20043,442Suspension 49%
20021,331Brakes 42%
20011,121Brakes 37%
2000949Brakes 40%

Where this comes from: the DVSA's anonymised results for every MOT test in Great Britain in 2025, counting tests of 2003 Mercedes-Benz CLKs registered in 2003. "Flagged" includes advisories, so it isn't the same as a fail rate. How we score