How often should the spark plugs be replaced in a Corolla Hybrid?

[AsherAnn]

Corolla Hybrid spark plugs should be replaced every 100,000 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 a skirt insulator and electrodes that appear gray-white, gray-yellow, or light brown. A properly functioning spark plug has a skirt insulator that is reddish-brown, with an electrode gap between 0.8-0.9mm and no signs of electrode burn. If the spark plugs are covered in 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, showing 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 for the spark plugs, the air-fuel mixture is too rich, or there is oil leakage.