1998 Mercedes-Benz SLK: common problems and MOT failures

What goes wrong more than usual on a 1998 Mercedes-Benz SLK?

Parts flagged at MOT more often on the 1998 Mercedes-Benz SLK than on all cars registered in 1998.

• Sub-frame3.8× usual
  Mercedes-Benz SLK

  10.3% All 1998 cars

  2.7%

  Failed outright at MOT: 0.1%, against 0.1% of all 1998 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.

• Headlights2× usual
  Mercedes-Benz SLK

  9.6% All 1998 cars

  4.7%

  Failed outright at MOT: 3.4%, against 2.5% of all 1998 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.

• Transmission oil leaks3.2× usual
  Mercedes-Benz SLK

  6.7% All 1998 cars

  2.1%

  Failed outright at MOT: 0.1%, against 0% of all 1998 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.

• Side repeaters4.3× usual
  Mercedes-Benz SLK

  4.7% All 1998 cars

  1.1%

  Failed outright at MOT: 2.3%, against 0.8% of all 1998 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.

• Brake lights1.9× usual
  Mercedes-Benz SLK

  7.6% All 1998 cars

  3.9%

  Failed outright at MOT: 6.9%, against 3.2% of all 1998 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.

Common 1998 Mercedes-Benz SLK MOT failures and advisories

The share of 1998 Mercedes-Benz SLK MOT tests where testers flagged each area, as a fail or an advisory. Rough prices are typical independent-garage costs.

• Lights and electrics
  34% of testsRough price £10–£80

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

• 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.

• Suspension
  32% 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
  25% 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
  12% 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
  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.

Questions to ask the seller before buying a 1998 Mercedes-Benz SLK

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

1. Any recent work on the sub-frame? (Flagged at MOT 3.8× as often on the 1998 Mercedes-Benz SLK as on other cars the same age.)
2. Any recent work on the headlights? (Flagged at MOT 2× as often on the 1998 Mercedes-Benz SLK as on other cars the same age.)
3. Any recent work on the transmission oil leaks? (Flagged at MOT 3.2× as often on the 1998 Mercedes-Benz SLK as on other cars the same age.)
4. Can I see the service history and receipts for any big jobs?