Used car guide

2003 Mercedes-Benz C-Class: common problems and what to check

What gets flagged at MOT on 2003 Mercedes-Benz C-Classs, from 3,648 tests in 2025, plus known faults and what to look at before you buy one.

3,648MOT tests in 2025
59%pass first time (all 2003 cars: 59%)
4,800typical miles a year
2.4×the usual rate for ball joint

What stands out

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

  • Ball joint2.4× usual
    Mercedes-Benz C-Class
    15% All 2003 cars
    6.3%

    Failed outright at MOT: 7.7%, 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.

  • Sub-frame2.3× usual
    Mercedes-Benz C-Class
    13% All 2003 cars
    5.6%

    Failed outright at MOT: 0.1%, against 0.3% of all 2003 cars. The rest were advisories or minor defects.

    Rough price £300–£1,000 our estimate

    At the viewing: Look underneath at the frame the suspension bolts to. Flaky rust or holes are expensive to fix.

  • Wheel bearings2.2× usual
    Mercedes-Benz C-Class
    8.5% All 2003 cars
    3.8%

    Failed outright at MOT: 0.7%, 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.

  • Anti-roll bar6.6× usual
    Mercedes-Benz C-Class
    4.6% 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.

  • Engine warning light2.1× usual
    Mercedes-Benz C-Class
    5.5% All 2003 cars
    2.6%

    Failed outright at MOT: 5.5%, against 2.6% 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.

Better than most

Rust around suspension or steering mountings: 1.9% here, against 6.6% of all 2003 cars. Sidelights: 2.1% here, against 6.1% of all 2003 cars.

By area

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

  • Suspension
    54% 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
    44% 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
    39% 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
    31% 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.

  • Exhaust and emissions
    16% 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.

  • Oil and fluid leaks
    14% 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.

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Other years

YearMOT testsMost flagged
20224,604Tyres 27%
20215,709Tyres 27%
20209,919Tyres 30%
201924,634Tyres 29%
201828,346Tyres 29%
201739,535Tyres 29%
201636,616Tyres 30%
201534,042Tyres 30%
201425,210Tyres 32%
201323,494Suspension 33%
201225,753Brakes 40%
201118,838Brakes 40%
201012,845Brakes 40%
200912,668Suspension 43%
200813,214Suspension 44%
200711,454Suspension 50%
20068,786Suspension 57%
20057,282Suspension 59%
20045,380Suspension 59%
20022,021Suspension 49%
20011,080Suspension 46%
2000523Suspension 41%

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