2015 Mercedes-Benz CLS diesel: common problems and MOT failures

What goes wrong more than usual on a 2015 Mercedes-Benz CLS diesel?

Parts flagged at MOT more often on the 2015 Mercedes-Benz CLS diesel than on all cars registered in 2015.

• Wheel bearings5.9× usual
  Mercedes-Benz CLS

  4.1% All 2015 cars

  0.7%

  Failed outright at MOT: 0.1%, against 0.3% of all 2015 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.

• Link ball joint covers3.7× usual
  Mercedes-Benz CLS

  2.6% All 2015 cars

  0.7%

  Failed outright at MOT: 1%, against 0.4% of all 2015 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.

• Engine warning light2.2× usual
  Mercedes-Benz CLS

  3.3% All 2015 cars

  1.5%

  Failed outright at MOT: 3.3%, against 1.5% of all 2015 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.

• Wheels2.2× usual
  Mercedes-Benz CLS

  2.4% All 2015 cars

  1.1%

  Failed outright at MOT: 1%, against 0.3% of all 2015 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 2015 Mercedes-Benz CLS diesel MOT failures and advisories

The share of 2015 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
  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.

• Brakes
  21% 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
  10% 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
  9% 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
  4% of testsRough price £15–£250

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

• Oil and fluid leaks
  2% 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.

Questions to ask the seller before buying a 2015 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 wheel bearings? (Flagged at MOT 5.9× as often on the 2015 Mercedes-Benz CLS diesel as on other cars the same age.)
2. Any recent work on the link ball joint covers? (Flagged at MOT 3.7× as often on the 2015 Mercedes-Benz CLS diesel as on other cars the same age.)
3. Any recent work on the engine warning light? (Flagged at MOT 2.2× as often on the 2015 Mercedes-Benz CLS diesel as on other cars the same age.)
4. Can I see the service history and receipts for any big jobs?