2026-10-08 · 5 min read
Subaru Outback Spark Plug Replacement Malaysia
The FB25 engine in BS Outback models uses four iridium spark plugs, rated for 60,000 km. The CB18 turbo in BT models also uses four iridium plugs, but the turbo environment benefits from inspection at 40,000–60,000 km, replacing earlier if signs of wear appear. Always use the Subaru-specified NGK or Denso iridium plugs — performance aftermarket plugs are generally not necessary for street use. Replacing plugs on the horizontally opposed boxer requires working from both sides of the engine bay.
Subaru Outback Spark Plugs
- Outback FB25 spark plugs: iridium at 100,000 km; EZ36 (6-cyl) also iridium at 100,000 km but has 6 plugs — H6 plug access requires more disassembly
- Outback H6 plug service: EZ36 6-cylinder plug service is more involved than FB25; requires special extension and careful reach; risk of dropping plug into engine bay is higher on H6 — work methodically
- Outback highway plug life: steady throttle highway driving is gentle on plugs; Outback highway-biased use means plugs comfortably reach 100,000 km interval without symptoms
- Outback plug inspection: remove all plugs at 100k service and inspect electrode wear and tip colour; tan/grey is healthy; white means lean; black sooty means rich or oil fouling — assess before reinstalling