Used car guide

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

What gets flagged at MOT on 2018 Mercedes-Benz CLAs, from 8,402 tests in 2025, plus known faults and what to look at before you buy one.

8,402MOT tests in 2025
80%pass first time (all 2018 cars: 81%)
8,200typical miles a year
2.9×the usual rate for wheels

What stands out

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

  • Wheels2.9× usual
    Mercedes-Benz CLA
    2.6% All 2018 cars
    0.9%

    Failed outright at MOT: 1.2%, 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.

  • Individual direction indicators5× usual
    Mercedes-Benz CLA
    2% All 2018 cars
    0.4%

    Failed outright at MOT: 0.5%, against 0.1% of all 2018 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.

  • Engine warning light1.9× usual
    Mercedes-Benz CLA
    2.1% All 2018 cars
    1.1%

    Failed outright at MOT: 2.1%, against 1.1% of all 2018 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.

By area

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

  • Tyres
    33% 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.

  • Lights and electrics
    7% 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
    6% of testsRough price £15–£250

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

  • Suspension
    6% 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.

  • Seats and seatbelts
    3% of testsRough price £80–£250

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

Looking at a Mercedes-Benz CLA?

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Other years

YearMOT testsMost flagged
2023696Tyres 13%
202211,367Tyres 29%
20219,544Tyres 30%
20207,521Tyres 31%
20198,245Tyres 32%
20178,245Tyres 33%
20167,601Tyres 33%
20156,749Tyres 33%
20144,276Tyres 33%
20132,080Tyres 34%

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