After how many kilometers does a car need to replace spark plugs?
2 Answers
Under normal maintenance conditions, 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 is recommended to follow the user manual. The following standards can be used as a reference 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 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's insulator skirt should be reddish-brown, 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 top, black streaks, cracks, or melted electrodes, the cause of the damage should be identified and the issue resolved before replacing the spark plug. 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 leakage.
I've been working in an auto repair shop for nearly 20 years and frequently encounter spark plug issues. Generally, vehicles need spark plug replacements every 30,000 to 100,000 kilometers, depending on the material: cheaper copper ones last about 30,000 km, while premium platinum or iridium plugs can go 80,000 to 100,000 km. Why such a big difference? It's because of driving conditions: city driving with frequent traffic jams wears spark plugs faster, so I recommend checking them every 40,000 km; highway driving is smoother, allowing extensions up to 80,000 km. I've seen customers delay too long - carbon buildup on spark plugs causes hard starts and skyrocketing fuel consumption, making repairs more expensive. During regular maintenance, have technicians check spark plug gaps and replace severely worn ones promptly. This saves money and prevents roadside breakdowns. Remember: the vehicle manual states minimum standards - don't believe manufacturer claims about 'never needing replacement,' that's just marketing!
