PartsTec oil filter (PTA421-0010) protects engine internals by trapping metallic particles, carbon deposits, and combustion by-products before they circulate through bearings and cylinder walls. Filtration parameters — for OE number: 03N 115 389 K, Supplementary Article/Supplementary Info: 763, Supplementary Article/Supplementary Info: 325, Supplementary Article/Supplementary Info: 428 — are matched to the engine's oil-pump flow rate to maintain full pressure without bypass-valve opening under normal operating conditions. Thread pitch, gasket diameter, and canister height are sized for AUDI, MAN, SEAT, SKODA and 1 other makes engines, enabling a straightforward swap at every service interval. Supersedes OE part numbers: 03N 115 389 A, 03N 115 389 B, 03N 115 389 K, 181226 and 19 more. PartsTec filtration products are manufactured under ISO/TS 16949 quality standards and carry the same multi-layer media construction found in dealer-supplied filters. Oil filters should be replaced at every oil change — typically every 10,000–15,000 miles or 12 months, whichever comes first — to prevent contaminant build-up that accelerates bearing and cylinder wear. Signs of a failing oil filter include low oil pressure warnings, engine noise at idle, dark or gritty oil on the dipstick, and in severe cases the oil pressure light illuminating on the dashboard. Oil filter replacement is one of the easiest DIY maintenance jobs — you need only a filter wrench (or strap wrench), a drain pan, and fresh oil; the entire oil-and-filter change takes under 30 minutes on most vehicles. Look for filters with an anti-drain-back valve (prevents dry starts), a silicone-treated gasket (resists hardening), and a high-burst-pressure rating — these details distinguish quality filters from budget alternatives. Using a quality oil filter protects your engine's internal components and helps maintain resale value — it is one of the lowest-cost, highest-impact maintenance items on any vehicle. Every part is dispatched with tracked delivery and a 14-day money-back guarantee with hassle-free returns.