2012 Mercedes-Benz SLK 1.8L Petrol · B24 NAR

Two fractured front coil springs within a twelve-month window define the mechanical risk profile of this Mercedes-Benz SLK, with the nearside unit failing at the May 2026 test and the offside unit having failed in May 2025. Both springs were replaced between tests, as evidenced by the subsequent pass certificates at the same garages, but the recurrence on opposite sides within a single year is a notable concern for a 2012 SLK. The most recent pass on 14 May 2026 was clean with no advisories recorded, suggesting the remedial work was completed to a satisfactory standard, yet front coil spring fractures are typically driven by a combination of corrosion at the spring seat, fatigue from age-related cyclic loading, and harsh kerbing impacts. Given the mileage and age, buyers should be alert to the possibility that further spring deterioration could occur on the rear axle, which has no MOT history of failure but remains a known weak point on R172 chassis SLK models of this vintage. The brake pipe corrosion advisories issued across all four corners at the October 2024 test introduce a secondary concern regarding the underbody plumbing, though these were classified as advisories rather than failures and the vehicle subsequently passed in both 2025 and 2026 with no recurrence on the brake system. With 69,989 miles recorded over fourteen years, this SLK has covered an average of roughly 5,000 miles annually, a usage pattern consistent with occasional leisure or weekend driving rather than daily commuting. There are no extended gaps in the MOT testing record, indicating the vehicle has remained on the road throughout its life and has not suffered a multi-year lay-up that might raise concerns about seized callipers, perished rubber seals, or a depleted 12V battery. However, low annual mileage on a sports convertible of this type often correlates with shorter journeys where the engine and exhaust do not reach full operating temperature, accelerating moisture accumulation in the oil and accelerating corrosion on exposed underbody components, which may partly explain the brake pipe surface corrosion noted in 2024. The accumulation rate appears steady rather than erratic, with no sudden jumps in recorded odometer readings between consecutive tests, lending confidence to the mileage accuracy. On a physical inspection, particular attention should be paid to the front suspension geometry following the twin spring failures, lifting the vehicle if possible to check for sagging at the affected corners and listening carefully for any clonks or resonant knocking over uneven surfaces, particularly when traversing speed bumps or potholes at low speed. The rear coil springs should also be examined for signs of corrosion pitting or deformation, as one failure often precedes another on older vehicles of this age. Regarding the brake pipe advisories, a thorough inspection underneath the vehicle should be carried out using a torch, focusing on the flexible hoses at each caliper and the rigid lines running along the chassis rails and subframe, looking for any flaking, deep pitting, or weeping of brake fluid, as surface corrosion covered in grease can mask more serious wall-thinning. On the road, the buyer should test the brakes firmly from higher speeds to confirm there is no sponginess, pull to one side, or pedal pulsation, and verify that the retractable hardtop operates cleanly through its full cycle, as roof mechanism failures are a known cost on this model. The drivetrain and ancillary systems appear to have remained trouble-free throughout the recorded test history, with no mention of exhaust leaks, driveshaft wear, or engine oil leaks, though a thorough underbonnet inspection for the characteristic oil weeps around the M271 or M276 engine variants, depending on which is fitted, would be prudent. The tyres should be checked for even tread wear across both axles, as inconsistent wear patterns can reveal underlying suspension geometry issues or alignment problems that may have contributed to the spring failures. Given the convertible body style, evidence of water ingress or damp carpets should be sought inside the cabin, particularly around the boot seal and door sills, as SLKs of this generation are known to suffer from drainage blockages in the roof mechanism. Overall, the MOT record points to a vehicle that is fundamentally sound but carries a documented pattern of front suspension fragility and emerging brake line corrosion that justifies a targeted pre-purchase inspection by a Mercedes-Benz specialist or independent garage familiar with the R172 platform.