At how many kilometers should spark plugs be replaced?

[JulietDella]

Spark plug replacement interval: Under normal maintenance conditions, replacement is recommended after driving 40,000 to 60,000 kilometers. However, this may vary depending on the brand and engine type, so it's advisable to follow the owner's manual. The following standards can be used as reference for maintenance replacement: Platinum spark plugs should be replaced at 40,000 km, ordinary nickel alloy spark plugs at 20,000 km, and iridium spark plugs at 60,000-80,000 km. Methods to determine if spark plugs are damaged: Remove the spark plug and observe its condition based on the following color indicators. A normal spark plug's insulator skirt and electrodes should appear gray-white, gray-yellow, or light brown. A properly functioning spark plug will have a reddish-brown insulator skirt with electrode gap between 0.8-0.9mm and no signs of electrode burning. If the spark plug has oil stains or deposits but isn't damaged, it can continue to be used after cleaning off the oil and deposits. If the spark plug is severely damaged with signs like blistering at the tip, black streaks, cracks, or melted electrodes, the cause of damage should be identified and corrected before installing new spark plugs. Additionally, if the spark plug appears smoke-blackened, it indicates either incorrect heat range selection or rich fuel mixture with oil leakage.