2017 Mercedes-Benz SLC diesel: common problems and MOT failures

What goes wrong more than usual on a 2017 Mercedes-Benz SLC diesel?

Parts flagged at MOT more often on the 2017 Mercedes-Benz SLC diesel than on all cars registered in 2017.

• Ball joint2.6× usual
  Mercedes-Benz SLC

  3.9% All 2017 cars

  1.5%

  Failed outright at MOT: 3.2%, against 0.7% of all 2017 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.

• Wheel bearings5.7× usual
  Mercedes-Benz SLC

  2.3% All 2017 cars

  0.4%

  Failed outright at MOT: 0.1%, against 0.2% of all 2017 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.

• Ball joint dust cover2.9× usual
  Mercedes-Benz SLC

  2.6% All 2017 cars

  0.9%

  Failed outright at MOT: 1.5%, against 0.4% of all 2017 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.

• Wheels2.6× usual
  Mercedes-Benz SLC

  2.3% All 2017 cars

  0.9%

  Failed outright at MOT: 0.6%, against 0.3% of all 2017 cars. The rest were advisories or minor defects.

  Rough price £70–£150 our estimate

  At the viewing: Check the tread on all four tyres, including the inside edges, and look for cracks or bulges.

Common 2017 Mercedes-Benz SLC diesel MOT failures and advisories

The share of 2017 Mercedes-Benz SLC diesel MOT tests where testers flagged each area, as a fail or an advisory. Rough prices are typical independent-garage costs.

• Tyres
  30% 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.

• Suspension
  11% 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
  9% 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
  8% of testsRough price £10–£80

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

• Wipers, windscreen and mirrors
  3% of testsRough price £15–£250

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

• Steering
  1% of testsRough price £100–£450

  At the viewing: On a straight road the steering wheel should sit straight. Feel for play or knocking when turning.

Questions to ask the seller before buying a 2017 Mercedes-Benz SLC diesel

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

1. Any recent work on the ball joint? (Flagged at MOT 2.6× as often on the 2017 Mercedes-Benz SLC diesel as on other cars the same age.)
2. Any recent work on the wheel bearings? (Flagged at MOT 5.7× as often on the 2017 Mercedes-Benz SLC diesel as on other cars the same age.)
3. Any recent work on the ball joint dust cover? (Flagged at MOT 2.9× as often on the 2017 Mercedes-Benz SLC diesel as on other cars the same age.)
4. Can I see the service history and receipts for any big jobs?