2018 Kia Optima diesel: common problems and MOT failures

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

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

• Brake pads1.6× usual
  Kia Optima

  17.8% All 2018 cars

  10.9%

  Failed outright at MOT: 4.2%, against 2% of all 2018 cars. The rest were advisories or minor defects.

  Rough price £75–£175 (one axle) ClickMechanic

  At the viewing: Listen for squealing or grinding when braking, and look through the wheel at how much pad is left.

• Braking performance2.7× usual
  Kia Optima

  3.2% All 2018 cars

  1.2%

  Failed outright at MOT: 0.6%, 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.

• Number plates1.9× usual
  Kia Optima

  2.7% All 2018 cars

  1.4%

  Failed outright at MOT: 0.2%, against 0.2% 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.

Common 2018 Kia Optima diesel MOT failures and advisories

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

• Tyres
  31% 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
  27% 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
  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.

• Seats and seatbelts
  4% of testsRough price £80–£250

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

• Oil and fluid leaks
  2% 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.

Questions to ask the seller before buying a 2018 Kia Optima 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 brake pads? (Flagged at MOT 1.6× as often on the 2018 Kia Optima diesel as on other cars the same age.)
2. Any recent work on the braking performance? (Flagged at MOT 2.7× as often on the 2018 Kia Optima diesel as on other cars the same age.)
3. Any recent work on the number plates? (Flagged at MOT 1.9× as often on the 2018 Kia Optima diesel as on other cars the same age.)
4. Can I see the service history and receipts for any big jobs?