Spark Plug Replacement Interval for Cars?
2 Answers
Under normal maintenance conditions, spark plugs should be replaced every 40,000 to 60,000 kilometers. However, this may vary depending on the brand and engine type, so it is recommended to follow the vehicle's user manual. The following standards can be referenced for maintenance and replacement: Platinum spark plugs should be replaced at 40,000 kilometers, standard 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 inspect its appearance to assess its condition. A normal spark plug will have an insulator skirt and electrodes that appear grayish-white, grayish-yellow, or light brown. A properly functioning spark plug will have a reddish-brown insulator skirt, an electrode gap between 0.8-0.9mm, and no signs of electrode burn. If the spark plug is covered in oil or deposits but not damaged, it can continue to be used after cleaning off the oil and deposits. If the spark plug is severely damaged—showing signs of blistering, black streaks, cracks, melted electrodes, etc.—the cause of the damage should be identified and the issue resolved before replacing the spark plug. Additionally, if the spark plug appears blackened as if smoked, it indicates the wrong heat range was selected, the air-fuel mixture is too rich, or engine oil is leaking into the combustion chamber.
As a professional frequently handling car maintenance, I've found that spark plug replacement intervals vary from person to person, typically needing replacement every 30,000 to 100,000 kilometers depending on your vehicle condition and driving habits. From my experience, copper-core spark plugs have poorer durability and require inspection and replacement every 30,000 kilometers; platinum ones can last about 60,000 to 80,000 kilometers; while premium iridium spark plugs perform even better, potentially lasting 100,000 kilometers or even longer without failure. If left unchanged for extended periods, the engine may experience ignition failure, slower starts, severe vehicle shaking, rapidly increasing fuel consumption, and even damage to internal engine components, doubling repair costs. I recommend car owners regularly monitor dashboard signals—if experiencing difficulty starting or reduced power, they should visit a repair shop for diagnostics. Early replacement can save fuel and extend vehicle lifespan; proper maintenance is always more cost-effective than expensive repairs later.
