How Often Should Spark Plugs Be Replaced in a Car?
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 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 a spark plug is damaged: Remove the spark plug and observe its condition based on the following appearance colors. A normal spark plug will have an insulator skirt and electrodes that appear gray-white, gray-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 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, showing 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 that the wrong heat range was selected or the air-fuel mixture is too rich, or there is oil leakage.
As a veteran driver with over ten years of experience, I recommend checking spark plugs every 30,000 kilometers. Most cars today use standard nickel-alloy spark plugs, which can last 40,000 to 50,000 kilometers, but platinum or iridium ones can go 70,000 to 80,000 kilometers. Once on the highway, I experienced weak acceleration and fuel consumption spiking to over 10 liters—after inspection, the spark plug electrodes were nearly worn flat. If you notice the engine shaking like it has asthma during startup or black smoke from the exhaust pipe, head to the repair shop immediately. Especially for those who love flooring the accelerator, change them more frequently—high RPMs are toughest on spark plugs. Don’t risk damaging the ignition coil just to save a few hundred bucks.
