Used car guide

2008 Mercedes-Benz SLK: common problems and what to check

What gets flagged at MOT on 2008 Mercedes-Benz SLKs, from 3,124 tests in 2025, plus known faults and what to look at before you buy one.

3,124MOT tests in 2025
68%pass first time (all 2008 cars: 57%)
4,400typical miles a year
1.9×the usual rate for rigid brake pipes

What stands out

Parts flagged at MOT more often on 2008 Mercedes-Benz SLKs than on all cars registered in 2008.

  • Rigid brake pipes1.9× usual
    Mercedes-Benz SLK
    18% All 2008 cars
    9.6%

    Failed outright at MOT: 2.8%, against 1.5% of all 2008 cars. The rest were advisories or minor defects.

    Rough price £100–£400 our estimate

    At the viewing: Ask to see underneath, or check the MOT advisories: corroded brake or fuel pipes get worse every year and fail the MOT when they do.

  • Ball joint1.8× usual
    Mercedes-Benz SLK
    11.4% All 2008 cars
    6.5%

    Failed outright at MOT: 6.7%, against 3.2% of all 2008 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.

Better than most

Engine oil leaks: 2.4% here, against 12.5% of all 2008 cars. Number plate lights: 1.9% here, against 8.9% of all 2008 cars.

By area

The share of 2008 Mercedes-Benz SLK MOT tests where testers flagged each area, as a fail or an advisory. Rough prices are typical independent-garage costs.

  • Suspension
    35% 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
    33% 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.

  • Tyres
    27% 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.

  • Lights and electrics
    22% of testsRough price £10–£80

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

  • Exhaust and emissions
    8% 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.

  • Wipers, windscreen and mirrors
    6% of testsRough price £15–£250

    At the viewing: Check for chips in the driver's view, and test the wipers and washers.

Looking at a Mercedes-Benz SLK?

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Other years

YearMOT testsMost flagged
20161,248Tyres 31%
20154,852Tyres 30%
20144,786Tyres 31%
20134,481Tyres 31%
20125,482Tyres 30%
20112,481Brakes 30%
20102,039Brakes 31%
20092,444Suspension 33%
20073,390Suspension 37%
20063,487Suspension 36%
20054,447Suspension 36%
20042,774Suspension 38%
20031,531Lights and electrics 35%
20021,637Brakes 35%
20011,856Brakes 33%
20001,515Lights and electrics 35%

Where this comes from: the DVSA's anonymised results for every MOT test in Great Britain in 2025, counting tests of 2008 Mercedes-Benz SLKs registered in 2008. "Flagged" includes advisories, so it isn't the same as a fail rate. How we score