How many kilometers should car spark plugs generally be replaced?

[LeJulia]

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, so it is recommended to follow 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 spark plugs are damaged: Remove the spark plugs and observe their appearance color to assess their condition. Normal spark plugs have an insulator skirt and electrodes that 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 burning. If the spark plug is oily or has 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. 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 the air-fuel mixture is too rich, with oil creeping up.

[SanMicah]

I found that the replacement mileage for spark plugs depends on the vehicle model and the material of the spark plugs. Generally, copper spark plugs have a shorter lifespan and need to be replaced every 30,000 to 50,000 kilometers, while platinum or iridium spark plugs can last 60,000 to 100,000 kilometers or even longer. My own car has been running for ten years with platinum spark plugs. The manual recommends replacing them every 60,000 kilometers, but I check the electrode gap every 50,000 kilometers and replace them earlier if there's significant wear or ignition difficulties. Last time, I delayed the replacement until 70,000 kilometers, and the engine started shaking, with fuel consumption increasing by 20%. After replacing the spark plugs, the engine started smoothly, and acceleration became more responsive. I recommend having a technician check the spark plug condition during regular maintenance, not just relying on mileage. If you frequently drive short distances, the spark plugs wear out faster. The cost of replacement is relatively low, around 100 yuan for materials, but neglecting it could lead to engine misfires or expensive repairs.

[MartinLee]

The timing for spark plug replacement isn't a fixed number. My car's manual suggests inspection at 40,000 km, and I'm using iridium plugs rated for 100,000 km. But in practice, it depends on driving habits - frequent starts in urban traffic accelerates wear and calls for earlier replacement. After four years with this vehicle, I changed the plugs at 50,000 km when noticing sluggish acceleration and gradually increasing fuel consumption. Post-replacement, the engine runs quieter with improved ignition efficiency and slightly better fuel economy.

Regular DIY checks are simple: listen for abnormal vibrations after starting the engine, or delayed ignition - these are telltale signs. I recommend replacement between 40,000-60,000 km based on symptoms, opting for long-life platinum or iridium materials. Though pricier upfront, they pay off in long-term reliability. Never delay too long - aged spark plugs may trigger the engine warning light or cause sudden breakdowns during highway driving.

[DiRafael]

Spark plug replacement typically occurs between 30,000 to 100,000 kilometers, with material being the key factor. Copper plugs for entry-level vehicles last 30,000-40,000 km; platinum for mid-range models 60,000-80,000 km; and iridium for high-end vehicles 80,000-100,000+ km. My common inspection method: check if the engine starts smoothly when cold—if it struggles or vibrates excessively, it's time for replacement. The cost is a few hundred yuan, but new plugs improve combustion efficiency and reduce carbon buildup. Long-term neglect can increase fuel consumption or damage the catalytic converter, leading to unnecessary expenses. Routine inspection every 40,000 km is recommended; replace if the electrode gap is too wide or the plug appears blackened.