How often should the spark plugs of a Corolla be replaced?
2 Answers
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, with an electrode gap between 0.8-0.9mm and no signs of electrode burning. If the spark plugs are contaminated 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, 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.
As a veteran driver who's driven a Corolla for hundreds of thousands of kilometers, I'm telling you that spark plugs usually need replacement every 60,000 to 80,000 kilometers - check your manual for specifics. If you're using cheap copper-core ones, you might need to change them every 30,000 km, while premium iridium ones can last over 100,000 km. Never delay replacement - late changes cause hard starts, poor fuel efficiency, and misfires. I once delayed replacement by just a few days and nearly stalled while climbing a hill. During routine maintenance, have your mechanic check the electrode gap - it should be around 0.8 to 1 mm for optimal performance. New spark plugs make your engine run smoother, accelerate better, and even save fuel. Always choose OEM-matched models - proper maintenance prevents major repairs. Don't forget to check them during oil changes.
