Used car guide

1999 Mercedes-Benz CLK: common problems and MOT failures

What MOT testers find on the Mercedes-Benz CLK first registered in 1999: we looked at the 2,494 MOTs these cars had during 2023–2025. Plus known faults and what to look at before you buy one.

2,494MOTs of 1999 cars, done in 2023–2025
67%pass first time (all 1999 cars: 63%)
4,000typical miles a year
2.1×the usual rate for headlights

What goes wrong more than usual on a 1999 Mercedes-Benz CLK?

Parts flagged at MOT more often on the 1999 Mercedes-Benz CLK than on all cars registered in 1999.

  • Headlights2.1× usual
    Mercedes-Benz CLK
    12.8% All 1999 cars
    6.2%

    Failed outright at MOT: 4%, against 3% of all 1999 cars. The rest were advisories or minor defects.

    Rough price £40–£400 our estimate

    At the viewing: Check both headlights on dipped and full beam, and look for cloudy or cracked lenses.

  • Wheel bearings1.9× usual
    Mercedes-Benz CLK
    10.9% All 1999 cars
    5.6%

    Failed outright at MOT: 1%, against 1% of all 1999 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.

  • Side repeaters5.3× usual
    Mercedes-Benz CLK
    6.3% All 1999 cars
    1.2%

    Failed outright at MOT: 2.8%, against 0.7% of all 1999 cars. The rest were advisories or minor defects.

    Rough price £10–£80 our estimate

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

  • Transmission oil leaks2.5× usual
    Mercedes-Benz CLK
    5% All 1999 cars
    2%

    Failed outright at MOT: 0.1%, against 0% of all 1999 cars. The rest were advisories or minor defects.

    Rough price £80–£600 our estimate

    At the viewing: Look under the engine and where the car is usually parked for fresh oil. Ask whether the leak has been looked at.

  • Individual direction indicators1.9× usual
    Mercedes-Benz CLK
    6.3% All 1999 cars
    3.4%

    Failed outright at MOT: 2.4%, against 1.5% of all 1999 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

Suspension arm bushes and joints: 2% here, against 5.9% of all 1999 cars. Body structure rust or damage: 2% here, against 4.6% of all 1999 cars.

Common 1999 Mercedes-Benz CLK MOT failures and advisories

The share of 1999 Mercedes-Benz CLK MOT tests where testers flagged each area, as a fail or an advisory. Rough prices are typical independent-garage costs.

  • Brakes
    40% 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
    38% of testsRough price £10–£80

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

  • Suspension
    36% 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.

  • Tyres
    28% 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
    17% 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.

  • Rust and bodywork
    9% of testsRough price £150–£1,000

    At the viewing: Check the sills, wheel arches and underneath for rust, and look along the panels for uneven gaps or paint.

Questions to ask the seller before buying a 1999 Mercedes-Benz CLK

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

  1. Any recent work on the headlights? (Flagged at MOT 2.1× as often on the 1999 Mercedes-Benz CLK as on other cars the same age.)
  2. Any recent work on the wheel bearings? (Flagged at MOT 1.9× as often on the 1999 Mercedes-Benz CLK as on other cars the same age.)
  3. Any recent work on the side repeaters? (Flagged at MOT 5.3× as often on the 1999 Mercedes-Benz CLK 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%
200411,851Suspension 48%
20038,824Suspension 44%
20024,862Brakes 42%
20014,042Brakes 39%
20003,319Brakes 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 1999. "Flagged" includes advisories, so it isn't the same as a fail rate. How we score