Can Spark Plugs Be Cleaned and Reused?
3 Answers
Spark plugs can be cleaned and reused if they show minimal wear. Generally, they should be replaced every 40,000 to 60,000 kilometers under normal maintenance conditions, but this may vary depending on the brand and engine type. It is recommended to follow the user manual for specific guidance. Platinum spark plugs should be replaced at 40,000 kilometers, standard nickel alloy spark plugs at 20,000 kilometers, and iridium spark plugs between 60,000 to 80,000 kilometers. Steps for replacing spark plugs: Open the hood and remove the plastic engine cover. Disconnect the high-voltage ignition wires, marking each wire according to its corresponding cylinder to avoid confusion. Use a spark plug socket to remove each spark plug one by one. During removal, check for any external debris such as leaves or dust, and ensure the area is thoroughly cleaned. Insert the new spark plug into the spark plug hole, hand-tighten it a few turns, and then use the socket to fully tighten it. Reinstall the high-voltage ignition wires in the correct firing order and reattach the cover.
A few days ago I tried cleaning the spark plugs for reuse, but it really wasn't a long-term solution. At that time, the engine had trouble starting, and thinking to save money, I removed the spark plugs for cleaning. Using a steel wire brush, I slowly scraped off the black carbon deposits, then measured and adjusted the gap to around 0.7mm. After reinstalling, the engine ran a bit smoother, but within less than two weeks it started shaking and smoking again. Turns out, when the electrodes wear down and become smaller, the spark intensity becomes insufficient, leading to incomplete combustion which increases fuel consumption and damages the engine. Spark plugs should be replaced every 20,000 to 30,000 kilometers; platinum ones like those in my car last longer. Although cleaning can serve as an emergency fix when spare parts aren't available, this method might only last a day or two at most, with significant long-term risks. Now I just replace them directly, and the car runs much smoother and is more reliable.
I often tinker with my beloved car and have researched cleaning spark plugs. Technically speaking, they can indeed be cleaned and reused, especially when there's only light carbon buildup. After removing carbon deposits with a small brush or sandblaster, you need to check the electrode gap—0.8 mm is ideal. However, in reality, electrodes corrode and thin over time, and cleaning can't restore them. Performance degrades quickly, leading to weaker ignition and affecting air-fuel mixture combustion. Modern cars use iridium plugs which are more durable, but cleaning can easily scratch the surface and cause insulation layer issues. Even with specialized carbon removal sprays, the effect is only temporary. Replacing with new spark plugs significantly improves ignition stability, enhances fuel efficiency, and prevents engine misfires. This small investment during car maintenance is truly worthwhile.
