Under what circumstances do spark plugs need to be replaced?
3 Answers
Spark plugs need to be replaced under the following circumstances: when the car exhibits symptoms such as difficulty starting, low power, excessive exhaust emissions, or increased fuel consumption; or when the spark plugs are severely damaged, showing phenomena like blistering at the top, black streaks, cracks, or melted electrodes. Methods to determine if a spark plug is damaged: Remove the spark plug and observe its condition based on the following appearance colors. A normal spark plug has 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 burn. If the spark plug is contaminated with oil 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 blistering, black streaks, cracks, or melted electrodes at the top, 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, with oil creeping up.
I've noticed that spark plugs typically need replacement in several situations, such as when the car has unstable idling or difficulty starting. Having driven for over a decade, I've experienced severe engine shaking multiple times, and upon inspection, found the spark plug electrodes worn out. Another telltale sign is significantly increased fuel consumption - last time after driving 70,000 kilometers, I had to refuel more frequently until replacing the spark plugs improved the situation. Additionally, sluggish acceleration and delayed throttle response often occur when spark plugs are severely carbon-fouled. Regular maintenance shouldn't be neglected either, with general recommendations suggesting inspection every 30,000 to 50,000 kilometers, especially for older vehicle models. Ignoring these issues may lead to more serious failures like catalytic converter damage, which can be extremely costly to repair. Therefore, timely replacement is crucial for enhancing engine performance and longevity.
As a frequent commuter, I believe spark plug replacement has the most direct impact on driving experience. When the car shakes at red lights or fails to start during cold starts, it's time for a check. A sudden spike in fuel consumption is also a major warning sign – once my monthly fuel costs increased by 20%, but returned to normal after changing the spark plugs. Spark plug lifespan depends on material: standard copper ones last about 40,000 km, while platinum ones can exceed 80,000 km. If you notice frequent ignition failures, address it early to avoid roadside breakdowns. During maintenance, casually check the electrode gap – replace if it's too wide or shows signs of erosion. This ensures both fuel efficiency and driving comfort.
