2015 Mazda 6 2.2L Diesel · SM15 OCK

The 2015 Mazda 6 passed its most recent MOT on 11 July 2025 at 67,719 miles, but the record reveals a maintenance pattern that has shifted from stable to deteriorating. Between 2022 and 2023 the vehicle sailed through with zero defects, yet the 2024 and 2025 tests show a clear escalation in corrosion-related advisories and suspension wear. The trend is worsening, not because the car has been neglected entirely, but because age-related decay is now catching up with previously sound components. Mileage accumulation sits at roughly 6,156 miles per year, which is typical for an eleven-year-old vehicle and suggests consistent use rather than long periods of storage. The jump from 55,962 miles in August 2022 to 59,000 miles by July 2023 represents about 3,000 miles in eleven months, and the subsequent rise to 64,012 miles by July 2024 adds another 5,000 miles in a year. The final interval from July 2024 to July 2025 shows just 3,707 miles, indicating the current pace has slowed slightly. There are no alarming gaps in the record, but the concentration of defects appearing from 2024 onward aligns with the car crossing the 60,000-mile threshold where rubber and corrosion issues typically accelerate. A buyer should pay close attention to the rear braking system. In the July 2024 failure, both rear brake pipes were flagged as excessively corroded and the offside front pipe was at imminent risk of fracture, with an active leak detected on another front pipe. By the July 2025 pass, the rear brake hoses themselves were noted with slight corrosion to the ferrules. This progression suggests the pipes were replaced or repaired between tests, but the underlying exposure to road salt and moisture remains unchanged. Inspect the full length of all brake lines for fresh coatings of grease or underseal that might be masking ongoing corrosion, and check for any weeping at unions or along the chassis rails. The rear suspension arms were flagged in 2025 as corroded but not seriously weakened, and the 2024 test recorded split and deteriorated rear bushes on both front lower arms alongside worn pins. These are not catastrophic failures, but they point to a vehicle that has spent significant time without undertray protection or has been driven on salted roads. Have a workshop put the car on a lift and check the rear subframe mounting points, the inner wings around the coil spring seats, and the sill seams beneath the plastic covers fitted at the last test. Those covers can trap moisture against bare metal, accelerating hidden corrosion that a cursory ground-level inspection will miss.