2009 Maserati Quattroporte 4.2L Petrol · M121 RTJ

A chronic exhaust gas leakage has been a feature of this Maserati Quattroporte across every recorded MOT since at least 2021, with the most recent pass on 29 September 2025 again flagging a minor leak at the central exhaust joint alongside fractured rear clamps. The defect signature is remarkably consistent: advisories on 2021-08-20, 2023-10-20, 2024-10-10 and the 2025 test all describe the same central joint leak with degraded or fractured clamps, indicating that the issue has been monitored rather than resolved over a four-year period. This pattern sits within a broader record that includes two failures, one of them particularly serious, on a near-side rear road wheel that was recorded as fractured on 19 August 2021. While the 2025 pass demonstrates that the car is presently roadworthy, the unresolved exhaust issue, combined with a major headlamp dipped beam failure in 2020 and a gearbox oil leak advisory in 2022, points to a vehicle that has accumulated chronic minor defects without full remediation. With 59,714 miles recorded against a 2009 build date, the Quattroporte has covered approximately 3,513 miles per year, a notably low annual accumulation for a car of this age and complexity. The MOT sequence shows annual testing from 2020 onwards with no obvious long gaps, but the mileage progression implies periods of limited use or extended standing, both of which are mechanically significant for an Italian luxury saloon of this vintage. Low utilisation tends to accelerate corrosion on ferrous components, degrade rubber suspension bushes and seals through lack of flexing, and allow brake discs and callipers to bind or seize from infrequent operation. The recorded advisories bear out these concerns: both rear coil springs were flagged as corroded in 2021, and rear tyre wear has been repeatedly noted at or close to legal limits, suggesting either prolonged standing followed by short stints or uneven usage patterns. For a prospective buyer, the exhaust system should be the primary inspection focus, as the same joint leak and fractured clamp arrangement has been reported repeatedly. On a cold start listen for ticking or hissing from beneath the centre of the car, and on a road test check for any change in exhaust note, vibration through the floor, or escalation of noise under load, as the four-year-old advisory may now have progressed to a more pronounced rupture. The rear suspension also warrants close attention given the corroded coil springs noted in 2021; on test drive, listen for clonks or squeaks over speed humps and uneven surfaces, and check for uneven rear ride height which would suggest a weakened or broken spring. Inspect the rear wheels and tyres carefully for any signs of cracking, kerbing damage, or corrosion around the rim, particularly remembering that one rear wheel was recorded as fractured in 2021, and verify even tyre wear across both rear axles. The 2022 gearbox oil leak advisory, although classed as not excessive, should be investigated by checking the underside of the car for fresh oil residue around the transmission housing and for any drips on the driveway surface after standing. Brake feel should be examined critically, as low-mileage cars frequently suffer from binding or seized callipers; test from a rolling start with light pedal pressure and confirm the car rolls freely without dragging. Finally, a thorough undertray-off inspection is advisable to check for any progression of corrosion on subframes, brake pipes, and suspension arms, as the combination of age, low mileage, and repeated advisories on corroded springs suggests that other ferrous components may now be approaching a similar condition even if not yet flagged.