2008 Mazda 6 diesel: common problems and MOT failures

What goes wrong more than usual on a 2008 Mazda 6 diesel?

Parts flagged at MOT more often on the 2008 Mazda 6 diesel than on all cars registered in 2008.

• Sub-frame3.7× usual
  Mazda 6

  21.7% All 2008 cars

  5.8%

  Failed outright at MOT: 1.8%, against 0.4% of all 2008 cars. The rest were advisories or minor defects.

  Rough price £300–£1,000 our estimate

  At the viewing: Look underneath at the frame the suspension bolts to. Flaky rust or holes are expensive to fix.

• Headlights2.5× usual
  Mazda 6

  22.4% All 2008 cars

  8.8%

  Failed outright at MOT: 8.5%, against 4% of all 2008 cars. The rest were advisories or minor defects.

  Rough price £40–£400 our estimate

  At the viewing: Check both headlights on dipped and full beam, and look for cloudy or cracked lenses.

• Number plate lights2.3× usual
  Mazda 6

  19.4% All 2008 cars

  8.5%

  Failed outright at MOT: 6.7%, against 2.3% of all 2008 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.

• Suspension arm4.5× usual
  Mazda 6

  12.7% All 2008 cars

  2.8%

  Failed outright at MOT: 0.7%, against 0.3% of all 2008 cars. The rest were advisories or minor defects.

  Rough price £120–£180 (one arm) ClickMechanic

  At the viewing: Listen for clunks over bumps and feel for the steering wandering. Worn arm bushes show as cracked rubber near the wheels.

• Ball joint dust cover3.2× usual
  Mazda 6

  13.7% All 2008 cars

  4.3%

  Failed outright at MOT: 4.8%, against 1.8% of all 2008 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.

Common 2008 Mazda 6 diesel MOT failures and advisories

The share of 2008 Mazda 6 diesel MOT tests where testers flagged each area, as a fail or an advisory. Rough prices are typical independent-garage costs.

• Suspension
  53% 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
  50% of testsRough price £10–£80

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

• Brakes
  47% 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
  36% 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.

• Oil and fluid leaks
  14% 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.

• Wipers, windscreen and mirrors
  12% of testsRough price £15–£250

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

Known faults on the 2008 Mazda 6 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.

• DPF clogging (2.0 diesel)

  2.0 diesel

  The 2.0 diesel has particular trouble with its diesel particulate filter clogging, even after long fast runs.

  At the viewing: Make sure no DPF or engine warning light shows, and ask what kind of driving it has done.

  Source: Carbuyer: used Mazda6 buying guide (2008-2012)

• Cam chain losing tension (2.2 diesel)

  2.2 diesel

  There are reports of the 2.2 diesel's cam chain losing tension, which can mean major engine work.

  At the viewing: Listen for a rattle from the engine, especially at start-up.

  Source: Carbuyer: used Mazda6 buying guide (2008-2012)

• Electrical faults and false blind-spot warnings

  All engines

  Electrical problems are reported, and the blind-spot lights on higher-spec cars can come on with nothing there.

  At the viewing: Test all the electrics and watch the mirror warning lights on the test drive.

  Source: Carbuyer: used Mazda6 buying guide (2008-2012)

Questions to ask the seller before buying a 2008 Mazda 6 diesel

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

1. Has the DPF ever been cleaned or replaced?
2. Has the timing chain been checked or replaced?
3. Any recent work on the sub-frame? (Flagged at MOT 3.7× as often on the 2008 Mazda 6 diesel as on other cars the same age.)
4. Any recent work on the headlights? (Flagged at MOT 2.5× as often on the 2008 Mazda 6 diesel as on other cars the same age.)
5. Any recent work on the number plate lights? (Flagged at MOT 2.3× as often on the 2008 Mazda 6 diesel as on other cars the same age.)
6. Can I see the service history and receipts for any big jobs?