2010 Volkswagen Polo 1.2L Petrol · BG10 ACJ

A persistent exhaust emissions issue sits at the centre of this Polo's MOT history, and it is the defining mechanical concern for any prospective buyer. Across two separate test attempts, the vehicle has failed on emissions criteria: once in 2022 for excessive carbon monoxide content after the second fast idle, and again in 2023 for a lambda reading outside specified limits after the second fast idle. Both failures point towards weaknesses in the engine management or catalyst system, such as a failing lambda sensor, worn oxygen sensor heater, vacuum leak, deteriorating catalytic converter, or ignition and fuelling irregularities that cause the mixture to run too rich. The recurrence of this defect category within roughly twelve months suggests the underlying cause was not permanently rectified between attempts. Aside from this, the record shows a clean pass in September 2023 with no advisories, a clean pass in 2021, and a clean pass in 2020, with a minor exhaust gas leak flagged as an advisory back in 2019 that may be consistent with the later emissions irregularities. Tyre-related advisories have also been noted on the nearside rear in both 2022 and 2023 and on the offside rear in 2023, with edge wear patterns recorded, suggesting either alignment irregularities or habitual loading that is unevenly distributing wear. With 133,527 miles recorded over sixteen years, this Polo has averaged approximately 8,345 miles per year, which is broadly typical for a vehicle of its age and segment. There are no multi-year gaps in the testing record that would suggest extended periods off the road, and the mileage progression between tests is consistent with regular use rather than long lay-ups or sudden bursts of high mileage. For a Polo of this age and mileage, this usage profile means the engine, gearbox, clutch, suspension, and braking components have all been worked steadily and are likely approaching or past the point where original factory items have been replaced at least once. The emissions failures and exhaust leak advisory should be viewed against this backdrop, as wear-related degradation of sensors, exhaust components, and engine seals becomes more probable as mileage accumulates past the 130,000 mark. For a test drive, particular attention should be paid to the symptoms associated with the emissions faults already recorded. A catalytic converter nearing the end of its service life often produces a metallic rattling under the floor from cold, while a failing lambda sensor can cause uneven idle, slight hesitation on gentle throttle inputs, and a faint smell of unburnt fuel from the exhaust. It is worth asking the seller to demonstrate a cold start, as excessive smoke from cold, particularly on the first start of the day, can indicate worn valve stem seals or piston ring wear that would also push emissions readings upwards. Any noticeable dip in power, surging at steady throttle, or illumination of the engine management warning light should be treated as direct evidence that the emissions fault flagged in 2023 may still be present or has resurfaced. The tyre edge wear advisories recorded on both rear tyres in 2022 and 2023 warrant a specific inspection of the rear suspension geometry. On the test drive, listen for clonking or knocking noises from the rear over uneven surfaces, particularly over speed humps and potholes, as worn rear suspension bushes or weakened coil springs can allow camber changes that produce exactly the kind of edge wear pattern noted in the advisories. With the vehicle stationary, inspect the rear shock absorbers for any signs of fluid leakage and check that the car sits level at both rear corners, as a sagging spring on one side is a common cause of uneven inner or outer edge wear. Finally, confirm the condition of all four tyres directly, looking for uneven tread depth across the width of the tyre, and verify that the rear registration plate lamps are functioning, given that both lamps were recorded as inoperative at the September 2023 failure.