2016 Smart Forfour: common problems and MOT failures

What goes wrong more than usual on a 2016 Smart Forfour?

Parts flagged at MOT more often on the 2016 Smart Forfour than on all cars registered in 2016.

• Exhaust emissions (catalyst)10.2× usual
  Smart Forfour

  5.1% All 2016 cars

  0.5%

  Failed outright at MOT: 5.1%, against 0.5% of all 2016 cars. The rest were advisories or minor defects.

  Rough price £175–£900 (catalytic converter) ClickMechanic

  At the viewing: Look for smoke when revving the warm engine and for engine or DPF warning lights.

• Ball joint2.4× usual
  Smart Forfour

  6.7% All 2016 cars

  2.8%

  Failed outright at MOT: 4.4%, against 1.5% of all 2016 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.

• Exhaust system2.4× usual
  Smart Forfour

  4.8% All 2016 cars

  2%

  Failed outright at MOT: 2.3%, against 0.5% of all 2016 cars. The rest were advisories or minor defects.

  Rough price £100–£500 (pipe or section) ClickMechanic

  At the viewing: Listen for blowing or rattling from underneath at idle, and look for black soot around joints.

• Brake lights2.1× usual
  Smart Forfour

  3.7% All 2016 cars

  1.8%

  Failed outright at MOT: 3.7%, against 1.4% of all 2016 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.

• Wipers1.8× usual
  Smart Forfour

  4.4% All 2016 cars

  2.5%

  Failed outright at MOT: 3.2%, against 1.6% of all 2016 cars. The rest were advisories or minor defects.

  Rough price £15–£60 our estimate

  At the viewing: Test the wipers and washers on every speed.

Common 2016 Smart Forfour MOT failures and advisories

The share of 2016 Smart Forfour 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
  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.

• Suspension
  17% 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.

• 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.

• Wipers, windscreen and mirrors
  9% of testsRough price £15–£250

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

• Exhaust and emissions
  7% of testsRough price £100–£1,200

  At the viewing: Look for black soot in the tailpipe, listen for blowing from the exhaust and check for engine or DPF warning lights.

Questions to ask the seller before buying a 2016 Smart Forfour

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

1. Any recent work on the exhaust emissions (catalyst)? (Flagged at MOT 10.2× as often on the 2016 Smart Forfour as on other cars the same age.)
2. Any recent work on the ball joint? (Flagged at MOT 2.4× as often on the 2016 Smart Forfour as on other cars the same age.)
3. Any recent work on the exhaust system? (Flagged at MOT 2.4× as often on the 2016 Smart Forfour as on other cars the same age.)
4. Can I see the service history and receipts for any big jobs?