How many kilometers should the spark plugs of a Corolla be replaced?

[SavannahAnn]

Corolla spark plugs should be replaced every 80,000 kilometers. Methods to determine if spark plugs are damaged: Remove the spark plugs and observe them. The condition of the spark plugs can be judged based on their appearance and color. Normal spark plugs have an insulator skirt and electrodes that appear gray-white, gray-yellow, or light brown. A properly functioning spark plug has a reddish-brown insulator skirt, an electrode gap between 0.8-0.9mm, and no signs of electrode burning. If the spark plugs are covered with oil or deposits but are not damaged, they can continue to be used after cleaning off the oil and deposits. If the spark plugs are severely damaged, with signs such as blistering at the top, black streaks, cracks, or melted electrodes, the cause of the damage should be identified. After troubleshooting, replace the spark plugs with new ones. Additionally, if the spark plugs appear black as if smoked, it indicates that the wrong heat range was selected or the air-fuel mixture is too rich, with oil rising.