Subaru Spark Plug Replacement Cost (Boxer)
Replace 4 NGK iridium plugs on a boxer engine — labor-intensive due to access.
$250–$500national average
Parts
$40–$100
Labor
2–2 hrs
DIY-friendly?
Yes (3/5)
Why this fails
Boxer spark plugs sit horizontally between engine and frame rails — labor is the cost.
What the job involves
- Remove battery (driver side) and intake snorkel (passenger side)
- Pull coil packs
- Anti-seize on threads, torque to spec (13 lb-ft)
- Reinstall coils and accessories
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If you delay this repair
Misfires, fuel-economy loss, fouled cats if delayed past 60k.
Save money
- • NGK Iridium IX ~$10/plug on Amazon
- • DIY in 90 min — biggest job in routine Subaru maintenance
- • Always replace all 4 even if only one fouled
FAQ
How much does subaru spark plug replacement cost (boxer) cost in 2026?
Expect $250–$500 at most US shops, parts plus labor.
How long does the job take?
2–2 labor hours typically.
Can I do this myself?
Yes — DIY difficulty 3/5.
What happens if I delay?
Misfires, fuel-economy loss, fouled cats if delayed past 60k.