2026-10-08 · 5 min read
Subaru WRX STI 100,000 km Service Malaysia
The 100,000 km service is the single most important milestone for the WRX STI EJ257. The timing belt replacement is the centrepiece — replace the belt, water pump, tensioner, and all idler pulleys as a complete kit. At this service also address: all four differential and DCCD fluids, spark plugs, cam seals inspection, coolant flush, brake fluid change, and a full suspension inspection. This service represents a major investment but is critical to engine survival.
Subaru WRX STI 100,000 km Service
- STI 100k TIMING BELT: EJ257 uses TIMING BELT — MUST be replaced at 100,000 km; timing belt failure = engine destruction; belt replacement includes water pump, tensioner, idler pulleys; this is the most critical 100k item on STI
- STI 100k full list: timing belt + water pump + tensioner, spark plugs (NGK iridium BKR7EIX for EJ257), coolant flush, brake fluid, gearbox oil (6-speed manual), front diff oil, rear diff oil, DCCD diff fluid, 4-wheel alignment
- STI 100k head stud: at 100k service, consider ARP head stud upgrade; if EJ257 has ever been overheated or run on RON95, ARP head studs are worthwhile; 100k service is natural point to perform this if not already done