2004 Ford Fusion 1.4L Diesel · RN53 CFD

The defining mechanical story for this 2004 Ford Fusion centres on a clear pattern of rear axle deterioration that escalated from advisory observations in early 2024 to outright Major failures by the close of that same year. On 24 January 2023 the vehicle passed with no recorded defects, and it carried that clean status through the 2022 and 2021 tests, suggesting the rear underbody components were acceptable at that point. However, the January 2024 test introduced Advisories for both rear coil springs showing corrosion, alongside advisories for both rear brake pipes corroded and coated in grease or other material. A repairable nearside stop lamp issue was also recorded against that test. Just twelve months later, on 30 January 2025, those same rear brake pipes had deteriorated to the extent that the nearside and offside rear brake pipes were both failed for excessive corrosion, and the offside rear coil spring had progressed from corroded to fractured or broken. A position lamp failure on the offside front was also recorded. The vehicle did subsequently pass on 30 January 2025 following repair, and the most recent test on 25 February 2026 was another pass, though it carried fresh advisories for a deteriorated rear registration plate and slight tyre damage or cracking. The overall trend indicates that the rear underbody corrosion has been arrested through repair, but the speed of deterioration within a single twelve-month cycle is a serious concern. The recorded mileage of 88,125 miles across approximately 22 years equates to an annual accumulation of roughly 4,006 miles, which is notably low for a vehicle of this age. MOT testing has been continuous on an annual basis since at least 2021, with no recorded gaps, indicating the vehicle has not been laid up or off-road for extended periods. This level of usage suggests the car has not been subjected to high-mileage wear on major drivetrain components, but it also means relatively few thermal cycles and limited mechanical conditioning, which can accelerate corrosion in vulnerable underbody areas and lead to drying of rubber components such as suspension bushes and boot or gaiter seals. The pattern observed in the test data is consistent with corrosion progression that is at least partly attributable to the underbody being exposed to winter road conditions without sufficient regular driving to keep components dry and active. For a prospective buyer, the most urgent area for physical inspection is the rear underbody structure, particularly the brake lines running to both rear wheels and the rear coil spring seats. The brake pipes were already excessively corroded in 2025, and any replacement sections should be closely examined for proper jointing, protective coating, and routing clear of the suspension arms. On a test drive, listen and feel for any knocking or clonking from the rear suspension over uneven surfaces, which would indicate worn trailing arm bushes, top mount issues, or compromised damper function, all common secondary consequences of prolonged corrosion around the spring platforms. Brake pedal feel should be assessed for sponginess or excessive travel, which would point to further corrosion or air ingress within the hydraulic system, and the rear of the car should be observed for pulling to one side under braking, suggesting a binding or seized rear caliper that may have developed alongside the pipework replacement. Beyond the rear axle, the tyre advisory recorded at the most recent test warrants a careful inspection of all four tyres for sidewall cracking, bulging, or uneven wear patterns, particularly on the driven axle, and the tread depth should be measured with a gauge rather than relying solely on the indicator bars. The front position lamp failure from 2025 should be confirmed as rectified by checking that all front and rear lighting functions correctly, including the stop lamps, which were also flagged as inoperative at the 2024 test. Given the vehicle's age and the documented corrosion progression, it is also prudent to have the vehicle raised on a ramp for a thorough inspection of the front subframe, suspension arms, anti-roll bar drop links, and fuel lines, as corrosion in one underbody area frequently indicates broader risk elsewhere. A compression test and an oil analysis may also be worthwhile given the engine's age, to confirm internal condition ahead of purchase.