2018 Kia Stonic diesel: common problems and MOT failures

What goes wrong more than usual on a 2018 Kia Stonic diesel?

Parts flagged at MOT more often on the 2018 Kia Stonic diesel than on all cars registered in 2018.

• Braking performance3.5× usual
  Kia Stonic

  4.2% All 2018 cars

  1.2%

  Failed outright at MOT: 1.2%, against 0.4% of all 2018 cars. The rest were advisories or minor defects.

  Rough price £100–£350 our estimate

  At the viewing: On a quiet road, brake firmly from about 30mph. The car should stop straight without pulling.

• Engine oil leaks2× usual
  Kia Stonic

  2% All 2018 cars

  1%

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

  Rough price £80–£600 our estimate

  At the viewing: Look under the engine and where the car is usually parked for fresh oil. Ask whether the leak has been looked at.

Common 2018 Kia Stonic diesel MOT failures and advisories

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

• Tyres
  27% 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
  25% 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
  7% 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
  5% 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
  3% of testsRough price £80–£250

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

Known faults on the 2018 Kia Stonic 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.

• Particulate filter warning (diesel)

  Diesel

  A DPF light that stays on can mean a blocked filter or a faulty sensor. No major issues are reported otherwise.

  At the viewing: Make sure no DPF warning shows.

  Source: What Car?: used Kia Stonic (2017 on) reliability

Questions to ask the seller before buying a 2018 Kia Stonic 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 braking performance? (Flagged at MOT 3.5× as often on the 2018 Kia Stonic diesel as on other cars the same age.)
2. Any recent work on the engine oil leaks? (Flagged at MOT 2× as often on the 2018 Kia Stonic diesel as on other cars the same age.)
3. Can I see the service history and receipts for any big jobs?