2005 Mercedes-Benz S-Class 3.7L Petrol · LM54 FNH

The most recent MOT test on 2021-09-20—with the vehicle now at 185,764 miles—shows a concerning pattern of repeated failures without recorded defects, despite two identical test dates and a prior failure in June 2021. This suggests either administrative errors in the MOT system or, more critically, that the vehicle was not roadworthy during those periods. The last successful test occurred over five years ago, in February 2020, at 178,661 miles, meaning the car has been off-road or untested for an extended period. Without a valid MOT since then, the vehicle is legally unroadworthy in the UK, and the lack of recent testing raises immediate questions about its current condition. The mileage progression indicates relatively stable usage, averaging around 8,800 miles annually, which is typical for a vehicle of this age. However, the gap between tests—particularly the 14-month interval between the 2018 and 2020 MOTs—is unusually long for a luxury car, where maintenance and compliance should be prioritised. The absence of any mileage between 2020 and 2021 suggests the vehicle may have been stored or used infrequently, which could accelerate deterioration in components like suspension bushes, coil springs, and brake calipers due to lack of motion. The recorded mileage itself does not indicate excessive wear beyond what would be expected for a 21-year-old vehicle, but the prolonged periods without testing are a red flag. Given the repeated MOT failures and the lack of a valid test since 2020, a buyer should prioritise a thorough inspection of critical high-wear areas. The suspension—particularly the rear coil springs and bushes—will likely show significant degradation after five years without testing, as will the brake system, where binding calipers or uneven wear on discs could have developed. Structural integrity should also be assessed, especially for corrosion in wheel arches, subframes, and sills, which are common failure points in older Mercedes-Benz models. The lack of recorded defects in past tests does not guarantee current safety; the vehicle may have passed by technicality rather than genuine roadworthiness. A pre-purchase inspection is essential to verify the condition of the drivetrain, exhaust emissions systems, and any potential hidden corrosion or fluid leaks.