Can Spark Plugs Continue to Be Used After Carbon Deposit Cleaning?
2 Answers
Spark plugs can continue to be used after carbon deposit cleaning. Location of Spark Plugs: Spark plugs are installed on the side or top of the engine. In earlier models, spark plugs were connected to the distributor via ignition cables. Over the past decade, most car engines have been modified to connect the ignition coil directly to the spark plug. Working Principle of Spark Plugs: Under high voltage, the air between the center electrode and the side electrode of the spark plug rapidly ionizes, forming positively charged ions and negatively charged free electrons. When the voltage between the electrodes reaches a certain level, the number of ions and electrons in the gas increases like an avalanche, causing the air to lose its insulating properties. A discharge channel forms in the gap, resulting in a "breakdown" phenomenon. At this point, the gas becomes a luminous body, known as a "spark." Along with the heat expansion, a "crackling" sound is also produced. The temperature of this electric spark can reach as high as 2000-3000°C, which is sufficient to ignite the air-fuel mixture in the engine combustion chamber.
As a veteran driver with nearly 30 years of experience, I'm quite knowledgeable about whether spark plugs can be reused after carbon deposit cleaning. Generally speaking, if cleaned properly, they can absolutely be reused. First, spray with carburetor cleaner or gently wipe the electrode area with a wire brush to remove the black carbon deposits—avoid using hard objects to prevent damage. After cleaning, check the spark plug electrode gap; use a feeler gauge to ensure it stays within the normal range of 0.8 to 1.0 mm. If the spark plug itself shows no cracks, deformation, or excessive electrode wear, reinstall it and test-start the engine. If idling and acceleration are smooth, it's good to go. However, be aware that performance after cleaning may not match that of a new plug. If you notice slight vibrations during high-speed driving or unexplained increases in fuel consumption, it's time for a replacement. I often do this myself—it saves money and is eco-friendly—but don't overdo it. After cleaning two or three times, it's safer to replace the plug. Regular inspection and maintenance are key to keeping a car running long-term, especially for older vehicles that need this extra layer of protection.
