Used car guide

2004 Mercedes-Benz CLK petrol: common problems and MOT failures

What MOT testers find on the petrol Mercedes-Benz CLK first registered in 2004 (petrol cars only): we looked at the 10,730 MOTs these cars had during 2023–2025. Plus known faults and what to look at before you buy one.

10,730MOTs of 2004 petrol cars, done in 2023–2025
62%pass first time (all 2004 cars: 57%)
5,000typical miles a year
2.1×the usual rate for ball joint

What goes wrong more than usual on a 2004 Mercedes-Benz CLK petrol?

Parts flagged at MOT more often on the 2004 Mercedes-Benz CLK petrol than on all cars registered in 2004.

  • Ball joint2.1× usual
    Mercedes-Benz CLK
    13.9% All 2004 cars
    6.7%

    Failed outright at MOT: 7.1%, against 3.2% of all 2004 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.

  • Wheel bearings1.7× usual
    Mercedes-Benz CLK
    6.4% All 2004 cars
    3.8%

    Failed outright at MOT: 0.5%, against 1.4% of all 2004 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 bar5× usual
    Mercedes-Benz CLK
    3% All 2004 cars
    0.6%

    Failed outright at MOT: 0.1%, against 0.1% of all 2004 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.

  • Airbag warning light2.2× usual
    Mercedes-Benz CLK
    3.8% All 2004 cars
    1.7%

    Failed outright at MOT: 3.6%, against 1.5% of all 2004 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.

  • Mirrors2.1× usual
    Mercedes-Benz CLK
    2.7% All 2004 cars
    1.3%

    Failed outright at MOT: 0.6%, against 0.3% of all 2004 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: 0.9% here, against 6.1% of all 2004 cars. Shock absorbers: 2.6% here, against 6.7% of all 2004 cars.

Common 2004 Mercedes-Benz CLK petrol MOT failures and advisories

The share of 2004 Mercedes-Benz CLK petrol MOT tests where testers flagged each area, as a fail or an advisory. Rough prices are typical independent-garage costs.

  • Suspension
    47% 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
    37% 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
    32% 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
    13% 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 an engine warning light.

Questions to ask the seller before buying a 2004 Mercedes-Benz CLK petrol

Ask before you travel to see it. A seller who knows the car will have answers, and receipts.

  1. Any recent work on the ball joint? (Flagged at MOT 2.1× as often on the 2004 Mercedes-Benz CLK petrol as on other cars the same age.)
  2. Any recent work on the wheel bearings? (Flagged at MOT 1.7× as often on the 2004 Mercedes-Benz CLK petrol as on other cars the same age.)
  3. Any recent work on the anti-roll bar? (Flagged at MOT 5× as often on the 2004 Mercedes-Benz CLK petrol as on other cars the same age.)
  4. Can I see the service history and receipts for any big jobs?

Looking at a Mercedes-Benz CLK?

Check the actual car: its own MOT history, mileage and what to ask the seller. Free, no sign-up.

Other years

Every year of the Mercedes-Benz CLK compared

YearMOT testsMost flagged
2010190Suspension 43%
20098,686Suspension 44%
20087,848Suspension 46%
200711,119Suspension 47%
20069,698Suspension 46%
200511,839Suspension 47%
20038,824Suspension 44%
20024,862Brakes 42%
20014,042Brakes 39%
20003,319Brakes 40%
19992,494Brakes 40%
1998686Suspension 40%
1997–Too few tests

Where this comes from: the DVSA's anonymised results for every MOT test done in Great Britain during 2023–2025, counting the MOTs of Mercedes-Benz CLK cars first registered in 2004. "Flagged" includes advisories, so it isn't the same as a fail rate. How we score