How Many Kilometers to Replace Spark Plugs?
3 Answers
Spark plug replacement interval: Under normal maintenance conditions, replace every 40,000 to 60,000 kilometers. However, this may vary depending on the brand and engine type. It is recommended to follow the user manual. The following standards can be referenced for maintenance 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 color to assess its condition. A normal spark plug's insulator skirt and electrode should 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 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, with 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 the wrong heat range was selected or the air-fuel mixture is too rich, with oil contamination.
I usually pay close attention to car maintenance, and the replacement interval for spark plugs does vary by vehicle. Regular nickel alloy ones need replacement every 20,000-30,000 km, while iridium or platinum ones can last 80,000-100,000 km. Just the other day, my neighbor's car had trouble starting, and when the mechanic opened it up, they found the electrodes were completely worn down. Cars that frequently drive short distances in the city are more prone to carbon buildup, so it's recommended to check the spark plug gap every 30,000 km. If you feel engine shaking during sudden acceleration or notice a sudden spike in fuel consumption, it's likely the spark plugs are due for retirement. I remember during my last maintenance visit, the technician used a borescope to show me the condition inside the cylinders and mentioned that prolonged neglect could lead to damage to the ignition coils, doubling the repair costs.
When my car reached 50,000 kilometers for maintenance, the mechanic said the original spark plugs could still last another 10,000 km. Actually, the manufacturer's manual is the most reliable source. Japanese cars generally require replacement at 100,000 km, while German cars need it around 60,000 km. Recently, I noticed the cold start time has become longer, which is caused by the aging of metal electrodes leading to insufficient ignition energy. If you frequently drive on highways, platinum spark plugs can last longer due to the effective high-temperature cleaning effect. A friend once opted for cheap aftermarket parts and ended up with air leakage after just 20,000 km, causing unstable idling. It's recommended to choose reputable brands like NGK or Bosch. Although they are more expensive, they are more durable.
