2009 Mercedes S-Class 3.0L Diesel · SL09 GSV

The most recent MOT test on 14 July 2026 resulted in a pass, but only after the vehicle initially failed the same day on a major defect concerning the nearside front suspension arm ball joint being excessively worn on the lower front arm. This is a significant suspension component failure and, given that the same nearside front wheel bearing showed slight play the same day, the front suspension and hub assemblies on this side warrant particular scrutiny. The broader maintenance trend across the last three years shows a clear pattern of deterioration. In 2024 and 2021 the vehicle passed with no recorded advisories, but the 2022, 2023, 2025, and 2026 tests have each carried multiple advisories relating to brakes, brake pipes, wheel bearings, tyres, and suspension components. The most recent test escalates this trend by introducing an outright major failure, suggesting that wear-related items are now accumulating faster than they are being addressed and that prospective buyers should not assume the car is simply in a tidy advisory state. Recorded mileage stands at 90,418 miles over an approximate 17-year life, equating to around 5,300 miles per year, which is substantially below the national average for a vehicle of this age. This low annual mileage indicates either a predominantly secondary vehicle, limited commuting use, or extended periods of standing. While lower mileage typically preserves engine internals and drivetrain components, it does carry specific risks for a vehicle of this age and class. Prolonged standing promotes corrosion of brake discs, binding of brake calipers, perishing of rubber components such as tyres, bushes, and flexible hoses, and degradation of fluids on a calendar basis rather than a usage basis. The fact that brake disc wear, brake pipe corrosion, and suspension component wear are all now appearing as advisories or defects suggests standing-related corrosion and rubber hardening may be accelerating component fatigue, and that mileage alone has not spared the chassis and running gear. For a prospective buyer, the recurring advisories on brake pipes coated in grease or other material on both sides front to rear should be treated as an early warning that the underlying pipework is corroding. While the application of a protective coating is a legitimate repair method, the repeat appearance of this advisory across multiple tests implies the corrosion is progressive and the pipes will likely require full replacement within the next service cycle. Similarly, the front brake pads and offside rear pads noted as wearing thin in the latest test should be inspected for remaining material thickness, and the rear brake discs should be checked for scoring depth; excessive lipping or pitting may necessitate disc replacement alongside the pad change. The nearside front lower arm ball joint, which caused the major failure, must be verified as having been replaced with a new component, and the nearside front wheel bearing play should be rechecked, ideally by jacking the wheel and confirming there is no roughness or lateral movement. On a test drive, listen for clonking or knocking from the front suspension over speed humps and uneven surfaces, and feel for vibration through the steering wheel which could indicate brake disc runout or a worn wheel bearing. Beyond the recorded defects, the age and low-mileage profile of this S-Class demands careful attention to time-served components. Tyres should be examined closely for sidewall perishing and cracking even if tread depth appears adequate, as a 17-year-old vehicle may be running tyres that have age-related degradation regardless of mileage. The 12V battery should be load-tested, since low-mileage use frequently leads to premature battery failure due to insufficient charging cycles. Brake fluid, coolant, and automatic transmission fluid all degrade on a calendar basis and should be checked for service history; Mercedes-Benz typically specifies brake fluid renewal every two years and coolant changes at extended intervals, and any missing entries in the service book should be factored into post-purchase costs. Given the recent major suspension failure, the brake pipe advisories, and the steady accumulation of chassis and brake-related wear, this vehicle warrants a pre-purchase inspection by a Mercedes-Benz specialist or a competent independent garage experienced with the brand, who can assess the broader condition of the front and rear suspension subframes, anti-roll bar links, and the full extent of any structural corrosion before committing to purchase.