2015 Subaru WRX STI 2.5L Petrol · AD65 WHH

The defining mechanical story of this 2016 Subaru WRX STI centres on a cluster of fluid-related advisories that have surfaced together, suggesting the powertrain and ancillary systems are entering a period where seals, gaskets and hydraulic components are beginning to show their age. The most recent MOT on 9 March 2026 recorded a pass, but it was accompanied by advisories noting the brake hydraulic reservoir sitting close to minimum, a non-excessive oil leak, and slight seepage from the power steering pipe or hose. The same date also produced a failure prior to the pass being issued, with major defects recorded against an inoperative horn and a malfunctioning tyre pressure monitoring system. Taken together, the picture is one of a vehicle that remains roadworthy on the day of test but is beginning to exhibit the kind of minor fluid losses and ancillary electrical faults consistent with a high-performance, turbocharged saloon approaching the 100,000 mile threshold. With 95,757 miles accumulated over roughly ten years, the annual mileage of approximately 9,576 miles sits squarely within typical parameters for the vehicle's age. There are no significant gaps in the testing pattern to suggest prolonged periods off the road, and no anomalous jumps in recorded mileage that would point to clocking or inconsistent use. Mechanically, this steady accumulation is broadly favourable for the chassis and structural integrity, as standing still for extended periods can be just as damaging to a Subaru of this type as high miles, particularly given the boxer engine's known sensitivity to short journeys and the AWD system's reliance on regular use to keep the transfer clutch and rear diff oil circulating properly. The mileage suggests the car has been driven consistently rather than left dormant, which is generally preferable for drivetrain longevity. For a prospective buyer, the advisory items flagged warrant close physical inspection and targeted questions on a test drive. The brake hydraulic reservoir being close to minimum, combined with the slight seepage from the power steering pipe, points to two separate hydraulic systems that may need attention; on a drive, listen for any squeal or grinding from the brakes on light application, check for a soft or spongy pedal feel, and pay attention to any whining or stiffness through the steering wheel, particularly when cold. The oil leak, described as not excessive, should be located by inspecting the underside for drips on the bellhousing area given the boxer layout, and the engine should be observed for any blue smoke on startup or under hard acceleration. The window tint minors are cosmetic and easily resolved, but the failed horn and TPMS items should be confirmed as rectified with evidence, as both are straightforward electrical fixes that speak to recent maintenance diligence. Finally, given this is an STI, a thorough test drive should specifically exercise the symmetrical AWD system, the multi-mode centre differential, and the clutch. Listen for any knocking or clonking from the front suspension on full lock or over speed bumps, as the inner tie rod ends and front lower arms are known wear items on these chassis. Feel for clutch slip under hard acceleration in third or fourth gear, and check for any vibration through the brake pedal under firm stopping which could indicate warped front discs. The tyres themselves should be inspected for even wear across both axles, as uneven rear wear can indicate a binding rear caliper or alignment issues following any rear diff work. A compression test and a borescope inspection of cylinder four, notorious for oil consumption issues in the EJ257 engine, would be money well spent before committing to a purchase at this mileage.