What is the replacement interval for spark plugs?
2 Answers
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. It is advisable to follow the instructions in the user manual. The following standards can be referenced for maintenance and replacement: Platinum spark plugs should be replaced at 40,000 kilometers, ordinary nickel alloy spark plugs at 20,000 kilometers, and iridium spark plugs at 60,000 to 80,000 kilometers. Methods to determine if a spark plug is damaged: Remove the spark plug and observe its appearance to assess its condition. A normal spark plug will have an insulator skirt and electrodes that appear gray-white, gray-yellow, or light brown. A properly functioning spark plug will have 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 signs such as blistering at the tip, 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.
I've driven quite a few cars and found that the replacement interval for spark plugs mainly depends on their type. For standard copper-core ones, you need to replace them every 20,000 miles or two years—otherwise, ignition becomes difficult, the engine might shake like an old tractor, and fuel efficiency drops. Platinum spark plugs are a bit better, lasting up to 60,000 miles without issues. The high-end iridium spark plugs can endure 100,000 miles or even longer. Driving habits also make a big difference—frequent city traffic jams accelerate wear, so early inspection is necessary. My old car once had its spark plugs burn out from delayed replacement, nearly damaging the engine. Since then, I always remind the mechanic during maintenance to check the electrode color—if it's black or carbon-fouled, replace it immediately to save money and hassle. Following the vehicle manual for regular replacements keeps the engine running smoothly, making the driving experience much more stable.
