2021 Mercedes 2551 12.8L Heavy oil · YJ70 MUO

The most recent MOT test on the 2021 Mercedes-Benz, conducted on 2026-07-29, resulted in a passing outcome with no recorded defects or advisories. The vehicle’s maintenance history over the past five years is predominantly stable, with five consecutive MOT passes spanning from 2023 to 2026, though there is a single failed test in 2024-01-09 that does not appear to have been rectified before the subsequent MOT. While the 2024 failure is the only recorded failure in the provided history, it suggests a potential area of concern that may warrant closer inspection, particularly if the vehicle has undergone any intervening repairs or if the failure was related to a recurring issue. The absence of further failures or advisories since then indicates that, if the 2024 issue was transient or addressed promptly, the vehicle’s roadworthiness is currently secure. The recorded mileage of 591,494 miles for a vehicle aged five years represents an exceptionally high annual usage rate of approximately 118,299 miles per annum, which is far above the average for its class. Such mileage accumulation typically indicates intensive use, potentially including long-distance travel, frequent short trips, or a combination of both, which can accelerate wear on critical components such as brakes, suspension, drivetrain, and fluid systems. The absence of significant mileage gaps between tests suggests consistent operation, but the rapid mileage growth may have led to cumulative stress on consumables like brake pads, tyre tread depth, and suspension elements. Additionally, prolonged exposure to high mileage without corresponding service intervals could result in issues such as degraded coolant, oil, or transmission fluid, or early signs of drivetrain wear, such as unusual noises from the differential or transmission. Given the vehicle’s high mileage and the recent MOT passing record, the prospective buyer should conduct a thorough mechanical inspection to identify any signs of wear or damage that may not have been flagged during the MOT. Focus on the braking system, particularly for signs of uneven brake pad or rotor wear, which could indicate underlying issues such as binding calipers, warped discs, or hydraulic brake failure. Listen for any grinding noises during braking, as this may signal metal-to-metal contact between pads and discs. Inspect the suspension for excessive play or clunking noises, especially when driving over bumps, which could point to worn suspension bushes, broken coil springs, or damaged control arms. Check for fluid leaks under the vehicle, particularly around the engine bay, transmission, and differential, as oil, coolant, or differential fluid leaks can lead to further damage if ignored. For fluid systems, the buyer should verify the condition of the coolant, brake fluid, and transmission fluid, as these can degrade over time even with moderate usage. Coolant should be checked for contamination or sediment, which could indicate a failing water pump or radiator. Brake fluid should be clear and free of moisture contamination, as absorbed moisture lowers the fluid’s boiling point and compromises braking performance. Transmission fluid should be checked for darkening or sludge, which may signal premature wear of internal components. Additionally, the tyre condition should be scrutinised for sidewall perishing or cracking, which can become critical if the vehicle has been stationary for extended periods, as the rubber can dry out and lose structural integrity. Finally, the 12V battery should be tested for charge capacity and terminal corrosion, as a failing battery can lead to electrical gremlins or starter issues, particularly under high-mileage conditions. If the vehicle has been driven regularly, ensure that the service book or maintenance records are up to date, as scheduled maintenance such as timing belt replacement, spark plug changes, and exhaust system servicing are often recommended at high mileage intervals.