Used car guide

2005 Mercedes-Benz SLK: common problems and MOT failures

What MOT testers find on the Mercedes-Benz SLK first registered in 2005: we looked at the 14,101 MOTs these cars had during 2023–2025. Plus known faults and what to look at before you buy one.

14,101MOTs of 2005 cars, done in 2023–2025
67%pass first time (all 2005 cars: 57%)
4,200typical miles a year
2.1×the usual rate for rust around sub-frame mountings

What goes wrong more than usual on a 2005 Mercedes-Benz SLK?

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

  • Rust around sub-frame mountings2.1× usual
    Mercedes-Benz SLK
    2.7% All 2005 cars
    1.3%

    Failed outright at MOT: 0.8%, 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: 5.3% here, against 13.4% of all 2005 cars. Number plate lights: 2.6% here, against 8% of all 2005 cars.

Common 2005 Mercedes-Benz SLK MOT failures and advisories

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
    34% 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
    26% 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
    9% 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
    7% 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.

Known faults on the 2005 Mercedes-Benz SLK

Reported by owners, mechanics and buying guides for this model and age. Check which engine the car has, as some apply to one engine only.

Questions to ask the seller before buying a 2005 Mercedes-Benz SLK

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

  1. Has the roof had any work?
  2. Any recent work on the rust around sub-frame mountings? (Flagged at MOT 2.1× as often on the 2005 Mercedes-Benz SLK as on other cars the same age.)
  3. Can I see the service history and receipts for any big jobs?

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

Every year of the Mercedes-Benz SLK compared

YearMOT testsMost flagged
20163,703Tyres 29%
201514,370Tyres 30%
201414,346Tyres 30%
201313,488Tyres 30%
201216,414Tyres 29%
20117,412Brakes 28%
20106,152Brakes 30%
20097,372Brakes 30%
20089,477Suspension 34%
200710,385Suspension 35%
200610,875Suspension 34%
20048,995Suspension 36%
20035,108Lights and electrics 35%
20025,561Brakes 34%
20016,267Brakes 33%
20005,296Brakes 34%
19994,124Brakes 34%
19983,041Lights and electrics 34%
19972,013Lights and electrics 36%
1996112Brakes 37%

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 SLK cars first registered in 2005. "Flagged" includes advisories, so it isn't the same as a fail rate. How we score