Used car guide

2018 Mercedes-Benz CLS: common problems and what to check

What gets flagged at MOT on 2018 Mercedes-Benz CLSs, from 947 tests in 2025, plus known faults and what to look at before you buy one.

947MOT tests in 2025
82%pass first time (all 2018 cars: 81%)
7,800typical miles a year
5×the usual rate for ball joint

What stands out

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

  • Ball joint5× usual
    Mercedes-Benz CLS
    6.5% All 2018 cars
    1.3%

    Failed outright at MOT: 1.9%, against 0.6% 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.

  • Wheels4.2× usual
    Mercedes-Benz CLS
    3.8% All 2018 cars
    0.9%

    Failed outright at MOT: 3.2%, against 0.3% 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.

By area

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

  • Tyres
    26% 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
    14% 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
    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.

  • Driveshafts and joints
    3% of testsRough price £60–£350

    At the viewing: On full steering lock, drive slowly and listen for clicking from the front wheels.

Looking at a Mercedes-Benz CLS?

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Other years

YearMOT testsMost flagged
20191,078Tyres 24%
20171,469Tyres 31%
20162,088Tyres 31%
20152,870Tyres 30%
20141,729Brakes 36%
20132,980Brakes 40%
20121,067Brakes 37%
20111,108Brakes 36%
2010981Brakes 37%
2009952Brakes 39%
20081,165Brakes 39%
20071,437Brakes 42%
20061,142Brakes 40%
2005824Brakes 36%

Where this comes from: the DVSA's anonymised results for every MOT test in Great Britain in 2025, counting tests of 2018 Mercedes-Benz CLSs registered in 2018. "Flagged" includes advisories, so it isn't the same as a fail rate. How we score