2012 Mercedes-Benz E 2.1L Diesel · B17 NAT

The defining mechanical story for this Mercedes-Benz E-Class centres on a notable corrosion event in July 2024, when brake pipes on both sides of the front axle were flagged as excessively corroded, with the offside front pipe actively leaking hydraulic fluid, a categorisation as a Dangerous defect at the time of test. The vehicle subsequently passed its next two MOT examinations in September 2024 and September 2025 with no defects recorded at all, suggesting that remedial work was carried out on the braking system, but the buyer must recognise that corrosion of underbody brake lines tends to recur once it has initiated, particularly on a fourteen-year-old chassis. Compounding the braking concern, a recurring advisory has been logged on the nearside front steering rack inner joint, first noted at the failed test in July 2024 and persisting as an advisory at the same test, indicating an underlying wear pattern in the steering gear that has not been resolved. The remaining advisories across the recorded history are comparatively minor in nature but form a consistent front-end wear picture, which is explored further in the guidance below. With 77,591 miles accumulated over approximately fourteen years, this E-Class records an annual mileage of roughly 5,500 miles, which is notably low for the vehicle's age and suggests extended periods of light use or possible standing between journeys. Such low utilisation typically places greater emphasis on the condition of rubber and polymer components, including suspension bushes, anti-roll bar linkages, brake hoses, and driveshaft gaiters, as well as on fluid systems where moisture accumulation and stagnation can accelerate internal degradation. However, the MOT record does not reveal extended multi-year gaps between tests, and the mileage progression appears reasonably consistent, with the only concentrated testing activity occurring in mid-2024 when the failed and follow-up pass took place within the same month. The relatively modest mileage does, however, imply that wear components such as the brake discs, pads, and clutch may retain significant useful life, provided they have not suffered from corrosion through infrequent use. For a prospective buyer, the priority area to scrutinise is the front braking and underbody corrosion status. A thorough inspection beneath the car on a ramp or over a pit is essential, paying particular attention to all brake pipes along their full length, the brake hoses, and any signs of surface rust or bubbling paintwork on structural components, given the speed at which the corrosion was judged dangerous in 2024. On test, the brake pedal should feel firm with no sponginess or excessive travel, and the car should pull up squarely without any pulling to either side under braking, which would suggest a binding caliper or a fluid restriction from a partially blocked or deformed pipe. The steering rack inner joint play, having been flagged twice, should be checked by rotating the wheel lock to lock with the engine running and feeling for any knocking, clonking, or roughness through the rack itself, as well as any inconsistency in steering self-centring. On the road, listen for knocking from the front suspension over uneven surfaces, particularly over speed humps and potholes, which could indicate the deterioration of anti-roll bar linkage ball joint dust covers that were severely deteriorated at the 2024 test and could have allowed water ingress and joint wear since. The suspension components flagged in earlier advisories, including the nearside front outer suspension arm pin or bush noted in 2021 and both front tyres wearing on edges in 2020, should also be evaluated. Edge wear on both front tyres is typically symptomatic of incorrect camber geometry, which may stem from worn suspension bushes or a bent component, so a four-wheel alignment check is advisable and any uneven shoulder wear on the current tyres should be examined closely. The rear tyre edge wear advisories from 2022 indicate that attention to wheel alignment is not a one-off concern for this vehicle. With the engine running from cold, listen for any timing chain rattle characteristic of the M271 or OM651 engines often fitted to this generation of E-Class, and inspect for any oil leaks around the sump, cam cover, and turbocharger area. Finally, given the predominantly urban or short-journey use implied by the mileage, verify that the vehicle has been serviced within the recommended Mercedes-Benz intervals, as long gaps between services are common on low-mileage cars and can lead to issues that an MOT test alone will not detect.