Used car guide

2018 Mercedes-Benz A-Class diesel: common problems and MOT failures

What MOT testers find on the diesel Mercedes-Benz A-Class first registered in 2018 (diesel cars only): we looked at the 59,571 MOTs these cars had during 2023–2025. Plus known faults and what to look at before you buy one.

59,571MOTs of 2018 diesel cars, done in 2023–2025
82%pass first time (all 2018 cars: 83%)
8,600typical miles a year
32%had tyres flagged

Common 2018 Mercedes-Benz A-Class diesel MOT failures and advisories

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

  • Tyres
    32% 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
    19% 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.

  • 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.

  • Lights and electrics
    6% 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
    4% 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
    2% of testsRough price £80–£250

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

Known faults on the 2018 Mercedes-Benz A-Class diesel

Reported by owners, mechanics and buying guides for this model and age. Check which engine the car has, as some apply to one engine only.

  • Oil leak and engine recalls

    All engines

    Recalls covered engine oil leaks and a fault that could cause engine failure.

    At the viewing: Look for oil under the car and around the engine, and ask a Mercedes dealer to check the VIN.

    Source: Carbuyer: used Mercedes A-Class Mk3 reliability

  • Driveshaft recall

    All engines

    A 2015 recall covered the driveshafts.

    At the viewing: Listen for clicking on full lock and feel for vibration when accelerating.

    Source: Carbuyer: used Mercedes A-Class Mk3 reliability

  • Electrical faults and rattles

    All engines

    Electrical issues were the top owner complaint, and early cars had seatbelt and dashboard rattles.

    At the viewing: Test every electric function and listen for rattles over bumps.

    Source: Carbuyer: used Mercedes A-Class Mk3 reliability

Questions to ask the seller before buying a 2018 Mercedes-Benz A-Class diesel

Ask before you travel to see it. A seller who knows the car will have answers, and receipts.

  1. Has all the recall work been done?
  2. Has the driveshaft recall been done?
  3. Have there been any electrical faults?
  4. Can I see the service history and receipts for any big jobs?

Looking at a Mercedes-Benz A-Class?

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

Other years

Every year of the Mercedes-Benz A-Class compared

YearMOT testsMost flagged
2026–Too new for MOT data
2025–Too new for MOT data
2024–Too new for MOT data
2023738Tyres 13%
202218,713Tyres 23%
202160,031Tyres 25%
2020252Tyres 27%
201925,714Tyres 29%
2017120,922Tyres 34%
2016113,202Tyres 33%
201579,796Tyres 34%
201468,784Tyres 34%
201343,599Tyres 33%
201215,427Brakes 32%
201116,093Brakes 37%
201018,296Brakes 41%
200920,571Brakes 47%
200819,943Brakes 47%
200717,982Brakes 45%
200613,121Brakes 47%
20058,721Brakes 41%
20043,765Brakes 52%
20033,911Brakes 53%
20022,845Brakes 51%
20011,837Brakes 49%
2000729Suspension 51%
1999496Suspension 53%
1998–Too few tests

Where this comes from: the DVSA's anonymised results for every MOT test done in Great Britain during 2023–2025, counting the MOTs of Mercedes-Benz A-Class cars first registered in 2018. "Flagged" includes advisories, so it isn't the same as a fail rate. How we score