If spark plugs are not replaced for a long time, it can cause various issues such as leakage in the vehicle's ignition system, increased fuel consumption, and reduced power. The most significant problem is difficulty in ignition, which affects the normal operation of the vehicle. Severe erosion of the spark plug—such as scarring, damage, or melting and erosion at the top of the electrode—indicates that the spark plug is damaged and should be replaced. Methods to determine if a spark plug is damaged: Remove the spark plug and observe its appearance. The condition of the spark plug can be judged based on the following color observations. A normal spark plug has an insulator skirt and electrode that appear gray-white, gray-yellow, or light brown. A properly functioning spark plug has an insulator skirt that is reddish-brown, with an electrode gap between 0.8-0.9mm and no signs of electrode burn. If the spark plug has oil stains or deposits but is not damaged, it can continue to be used after cleaning off the oil and deposits. If the spark plug is severely damaged, showing signs such as scarring, black streaks, cracks, or melted electrodes, the cause of the damage should be identified. After troubleshooting, replace the spark plug with a new one. Additionally, if the spark plug appears black as if smoked, it indicates that the wrong heat range was selected or that the air-fuel mixture is too rich, or that engine oil is leaking into the combustion chamber.
