When should car spark plugs generally be replaced?
2 Answers
Under normal maintenance conditions, car spark plugs should be replaced after driving 40,000 to 60,000 kilometers. However, this may vary depending on the brand and engine type, so it's recommended to follow the owner's 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 spark plugs are damaged: Remove the spark plug and observe its appearance color to assess its condition. A normal spark plug's insulator skirt and electrodes should appear gray-white, gray-yellow, or light brown. A properly functioning spark plug's insulator skirt should be reddish-brown, with an electrode gap between 0.8-0.9mm and no signs of electrode burning. If the spark plug has oil stains or deposits but isn't damaged, it can continue to be used after cleaning off the oil and deposits. If the spark plug is severely damaged with signs like blistering at the top, black streaks, cracks, or melted electrodes, the cause of damage should be identified. After troubleshooting, replace with a new spark plug. Additionally, if the spark plug appears smoke-blackened, it indicates incorrect heat range selection, rich fuel mixture, or oil leakage.
I've driven several cars, and generally, spark plugs should be replaced every 40,000 to 50,000 kilometers, depending on the vehicle's manual recommendations. My previous Honda started to show slight hesitation at 40,000 km, and fuel consumption increased. The mechanic checked and said the aging spark plugs were affecting ignition efficiency. After replacing them, the car ran much smoother immediately. Don't delay too long, or the engine might misfire, leading to more expensive repairs. Daily driving habits also matter—frequent stop-and-go city driving causes faster wear, so check them earlier. If you drive less on highways, they can last longer. Regular copper plugs need more frequent replacement, while platinum or iridium plugs have higher durability and can easily last 70,000 to 80,000 km. It's wise to check the spark plugs' condition during regular maintenance.
