2004 Daihatsu Sirion 1.3L Petrol · HW04 AEK

At the mechanical core of this 22 year old Daihatsu Sirion lies an exhaust emissions failure that warranted three major defects on 24 January 2025, before the same vehicle returned later that same day with a clean pass and no recorded defects. The pattern of subsequent testing has remained stable, with the most recent MOT on 21 January 2026 recorded as a pass with no defects or advisories noted. Prior to the 2025 episode, the car passed through 2024 with a clean sheet, but the 2023 test on 23 January left two advisory items that remain relevant to any prospective buyer today: corrosion noted on the nearside rear fuel pipe, and undertrays and exhaust fitments preventing full inspection of components beneath. A pass certificate is not equivalent to a clean bill of health, and the emissions failure alongside the persistent fuel pipe advisory point to components that warrant direct physical scrutiny rather than assumption. Mileage recorded at 122,466 across roughly two decades of MOT history translates to an annual accumulation of approximately 5,567 miles, which is notably low for a vehicle of this age. While low annual mileage can reduce wear on major drivetrain components such as the clutch, gearbox and engine internals, it can equally expose the car to the effects of extended standing periods. Corrosion on fuel lines as noted in 2023 is a typical outcome of under use rather than over use, particularly in UK conditions where moisture sits in brake and fuel systems that are not regularly flushed by sustained operation. The MOT history does not contain any record of an SORN declaration or long gaps between tests, with annual entries continuing each January, suggesting the vehicle has been in regular if limited use rather than laid up for prolonged periods. For a prospective buyer, the nearside rear fuel pipe advisory recorded in 2023 is the single most important item to inspect in person. The component should be physically examined for live corrosion, scaling, flaking or any sign of weeping around joints and unions, paying particular attention to the section running along the underside of the body where road spray and winter salt accumulate. Given that the 2023 examiner also flagged undertrays as obstructing full inspection, it would be prudent to arrange for the undertray to be removed during any pre purchase examination so that the full length of the fuel line, the exhaust system, subframe mounting points and suspension components can be properly assessed for corrosion. Replacement of a corroded fuel pipe is generally a modest cost in isolation but the work can escalate if the corrosion has migrated to surrounding lines or brackets. On a road test, particular attention should be paid to any hesitation, misfire or unusual exhaust smell which would suggest that the 2025 emissions failure has potentially returned. The engine should be started from cold and watched for excessive smoke, particularly blue tinged smoke from the tailpipe which would indicate oil burning, or dense white smoke that does not clear once the engine warms up, suggesting head gasket or coolant related issues. Listen for any clonks or knocking from the rear suspension over uneven road surfaces, which would indicate worn bushes or corroded mounting hardware, and feel for pulling under braking which can betray a seized or binding caliper. Finally, given the relatively low annual mileage, the handbrake mechanism, rear brake adjusters and any seldom used electrical features such as the registration plate lamps flagged as defective in 2023 should all be manually operated during the inspection to confirm they have not seized from lack of use.