Used car guide

2005 Mercedes-Benz SLK: common problems and what to check

What gets flagged at MOT on 2005 Mercedes-Benz SLKs, from 4,447 tests in 2025, plus known faults and what to look at before you buy one.

4,447MOT tests in 2025
68%pass first time (all 2005 cars: 58%)
4,000typical miles a year
2×the usual rate for rust around sub-frame mountings

What stands out

Parts flagged at MOT more often on 2005 Mercedes-Benz SLKs than on all cars registered in 2005.

  • Rust around sub-frame mountings2× usual
    Mercedes-Benz SLK
    3% All 2005 cars
    1.5%

    Failed outright at MOT: 0.9%, against 0.3% of all 2005 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.

Better than most

Engine oil leaks: 6.1% here, against 14.5% of all 2005 cars. Number plate lights: 3% here, against 8.2% of all 2005 cars.

By area

The share of 2005 Mercedes-Benz SLK MOT tests where testers flagged each area, as a fail or an advisory. Rough prices are typical independent-garage costs.

  • 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.

  • Brakes
    31% 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
    27% 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.

  • Oil and fluid leaks
    8% 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.

Looking at a Mercedes-Benz SLK?

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

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%
20083,124Suspension 35%
20073,390Suspension 37%
20063,487Suspension 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 2005 Mercedes-Benz SLKs registered in 2005. "Flagged" includes advisories, so it isn't the same as a fail rate. How we score