How Often Should the Spark Plugs Be Replaced in a Subaru Forester?

[DelJeffrey]

Subaru Forester spark plug replacement is primarily based on mileage, with replacement recommended every 40,000 to 60,000 kilometers. Spark plugs are a crucial component of a gasoline engine's ignition system, as they introduce high voltage into the combustion chamber and create a spark by jumping the electrode gap, thereby igniting the combustible air-fuel mixture in the cylinder. Steps for replacing spark plugs: Open the hood, lift the engine's plastic cover, and remove the high-voltage ignition wires. Mark each cylinder's position to avoid confusion. Use a spark plug socket to remove the spark plugs one by one. While removing them, check for any external debris like leaves or dust and ensure they are thoroughly cleaned. Place the new spark plug into the spark plug hole, hand-tighten it a few turns, and then use the socket to tighten it further. Reinstall the removed high-voltage ignition wires in the firing order, then secure the cover.