Is Cleaning Spark Plugs Useful?
2 Answers
Cleaning spark plugs is not useful. When spark plugs reach the end of their lifespan, their internal components age, leading to poor acceleration and increased fuel consumption, which cleaning cannot resolve. The gap between the spark plug electrodes significantly affects their performance. If the gap is too small, the spark will be weak and prone to carbon buildup and leakage. If the gap is too large, the required breakdown voltage increases, making the engine harder to start and more likely to misfire at high speeds. Therefore, the spark plug gap should be properly adjusted. The standard for spark plugs typically uses the heat value to characterize their thermal properties. The heat value indicates the balance between heat absorption and dissipation in the spark plug insulator's skirt. A higher heat value means better heat absorption and dissipation balance. Thus, hot-type spark plugs have a low heat value, while cold-type spark plugs have a high heat value. Generally, high-power, high-compression engines use cold-type spark plugs with high heat values, whereas low-power, low-compression engines use hot-type spark plugs with low heat values.
With over 20 years of driving experience, I've cleaned spark plugs many times. Especially when driving older cars, spark plugs tend to accumulate carbon deposits, causing hard starts or lack of power. I'd remove them and scrub off the carbon with a toothbrush dipped in gasoline. After reinstalling, the engine would fire up smoothly and accelerate more powerfully. But this fix was short-lived—after just 100-200 kilometers, the problems returned because the electrode gap widens over time, and cleaning can't address the root issue. Now I know spark plugs themselves are inexpensive; a new set costs just a few dozen yuan and lasts tens of thousands of kilometers, saving the hassle of repeated cleaning. So if spark plugs are only slightly dirty, cleaning can provide temporary relief. But if the car frequently has issues, replacing them outright is the best solution—safe driving is more important.
