Used car guide

2004 Mazda 6: common problems and what to check

What gets flagged at MOT on 2004 Mazda 6s, from 269 tests in 2025, plus known faults and what to look at before you buy one.

Small sample: only 269 of these were MOT tested in 2025, so treat the percentages as rough. The known faults below don't depend on it.

269MOT tests in 2025
54%pass first time (all 2004 cars: 58%)
4,200typical miles a year
3×the usual rate for sub-frame

What stands out

Parts flagged at MOT more often on 2004 Mazda 6s than on all cars registered in 2004.

  • Sub-frame3× usual
    Mazda 6
    18.6% All 2004 cars
    6.2%

    Failed outright at MOT: 0%, against 0.3% of all 2004 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.

  • Suspension arm3.3× usual
    Mazda 6
    13.4% All 2004 cars
    4.1%

    Failed outright at MOT: 0%, against 0.4% of all 2004 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.

  • Rust around suspension or steering mountings2.4× usual
    Mazda 6
    16% All 2004 cars
    6.6%

    Failed outright at MOT: 7.4%, against 3% of all 2004 cars. The rest were advisories or minor defects.

    Rough price £100–£450 our estimate

    At the viewing: On a straight road the steering wheel should sit straight. Listen for knocks when turning, and check the steering feels even.

  • Chassis rust or damage3× usual
    Mazda 6
    11.9% All 2004 cars
    4%

    Failed outright at MOT: 4.5%, against 1.2% of all 2004 cars. The rest were advisories or minor defects.

    Rough price £150–£1,000 our estimate

    At the viewing: Check the sills, wheel arches and underneath for rust, and look along the panels for uneven gaps or paint.

By area

The share of 2004 Mazda 6 MOT tests where testers flagged each area, as a fail or an advisory. Rough prices are typical independent-garage costs.

  • Suspension
    54% 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
    42% 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
    42% 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
    29% 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.

  • Rust and bodywork
    25% of testsRough price £150–£1,000

    At the viewing: Check the sills, wheel arches and underneath for rust, and look along the panels for uneven gaps or paint.

  • Wipers, windscreen and mirrors
    14% of testsRough price £15–£250

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

Looking at a Mazda 6?

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Other years

YearMOT testsMost flagged
2022716Tyres 16%
2021658Tyres 23%
20201,048Tyres 24%
20194,395Tyres 27%
20183,210Tyres 29%
20174,653Tyres 30%
20166,752Suspension 30%
20156,282Suspension 36%
20145,727Suspension 41%
20133,778Suspension 44%
20122,571Suspension 45%
20113,366Suspension 45%
20104,225Suspension 49%
20093,024Suspension 51%
20082,532Suspension 52%
20071,782Suspension 57%
2006972Suspension 51%
2005566Suspension 55%
2003126Suspension 56%

Where this comes from: the DVSA's anonymised results for every MOT test in Great Britain in 2025, counting tests of 2004 Mazda 6s registered in 2004. "Flagged" includes advisories, so it isn't the same as a fail rate. How we score