2018 Mercedes-Benz CLS diesel: common problems and MOT failures

What goes wrong more than usual on a 2018 Mercedes-Benz CLS diesel?

Parts flagged at MOT more often on the 2018 Mercedes-Benz CLS diesel than on all cars registered in 2018.

• Ball joint7.3× usual
  Mercedes-Benz CLS

  7.3% All 2018 cars

  1%

  Failed outright at MOT: 2.4%, against 0.4% of all 2018 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.

• Wheels4.4× usual
  Mercedes-Benz CLS

  3.5% All 2018 cars

  0.8%

  Failed outright at MOT: 2.6%, against 0.2% of all 2018 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 2018 Mercedes-Benz CLS diesel MOT failures and advisories

The share of 2018 Mercedes-Benz CLS diesel MOT tests where testers flagged each area, as a fail or an advisory. Rough prices are typical independent-garage costs.

• 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.

• Brakes
  15% 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
  9% 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.

• Lights and electrics
  4% 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.

• Seats and seatbelts
  1% of testsRough price £80–£250

  At the viewing: Pull each seatbelt sharply. It should lock, and retract cleanly.

Questions to ask the seller before buying a 2018 Mercedes-Benz CLS 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 7.3× as often on the 2018 Mercedes-Benz CLS diesel as on other cars the same age.)
2. Any recent work on the wheels? (Flagged at MOT 4.4× as often on the 2018 Mercedes-Benz CLS diesel as on other cars the same age.)
3. Can I see the service history and receipts for any big jobs?