Used car guide

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

What gets flagged at MOT on 2018 Mercedes-Benz Xs, from 1,257 tests in 2025, plus known faults and what to look at before you buy one.

1,257MOT tests in 2025
80%pass first time (all 2018 cars: 81%)
10,400typical miles a year
3.5×the usual rate for number plate lights

What stands out

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

  • Number plate lights3.5× usual
    Mercedes-Benz X
    6.3% All 2018 cars
    1.8%

    Failed outright at MOT: 1%, against 0.6% of all 2018 cars. The rest were advisories or minor defects.

    Rough price £5–£40 our estimate

    At the viewing: Check the number plate lights work and the plates are clean and legal.

  • Anti-roll bar bushes and joints21× usual
    Mercedes-Benz X
    4.2% All 2018 cars
    0.2%

    Failed outright at MOT: 0.6%, against 0% of all 2018 cars. The rest were advisories or minor defects.

    Rough price £100–£280 (pair of drop links) Checkatrade

    At the viewing: Drive slowly over bumps and listen for a knock or rattle from the front. Worn anti-roll bar links are a cheap fix.

  • Engine warning light4.6× usual
    Mercedes-Benz X
    5.1% All 2018 cars
    1.1%

    Failed outright at MOT: 5.1%, 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.

  • Drive shaft (CV) joints3.5× usual
    Mercedes-Benz X
    3.9% All 2018 cars
    1.1%

    Failed outright at MOT: 0.6%, against 0.6% of all 2018 cars. The rest were advisories or minor defects.

    Rough price £60–£350 our estimate

    At the viewing: Drive slowly on full steering lock in both directions and listen for clicking. Look for split rubber boots behind the front wheels.

  • Ball joint dust cover4.4× usual
    Mercedes-Benz X
    3.5% All 2018 cars
    0.8%

    Failed outright at MOT: 0.1%, against 0.3% 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.

Better than most

Tyre condition: 3.4% here, against 13.9% of all 2018 cars.

By area

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

  • Brakes
    20% 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.

  • Tyres
    19% 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.

  • Lights and electrics
    13% of testsRough price £10–£80

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

  • 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.

  • Wipers, windscreen and mirrors
    7% 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
    5% 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.

Looking at a Mercedes-Benz X?

Check the actual car: its own MOT history, mileage and what to ask the seller. Free, no sign-up.

Other years

YearMOT testsMost flagged
2020666Tyres 16%
20191,626Tyres 18%

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