Is Cleaning Spark Plugs Useful?
4 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.
Having repaired cars for over a decade, I've seen countless cases regarding spark plug cleaning. Cleaning can remove carbon deposits and temporarily restore the ignition system's functionality—for instance, some cars with slow starts show immediate improvement after cleaning. However, the key lies in the spark plug's condition: if the electrodes are severely eroded or the gap is uneven, cleaning might actually accelerate damage. I advise car owners not to rely too much on cleaning. Nowadays, spark plugs are inexpensive, costing just a few dozen yuan each, and replacing them yourself is straightforward. New spark plugs offer more reliable performance and longevity. At best, cleaning is an emergency measure; prolonged use increases the risk of breakdowns. Remember, safety comes first—if ignition issues arise, prioritize inspection and replacement with new parts.
As a millennial car owner, when I first started tinkering with cars to save money, I tried using spark plug cleaners. A ten-yuan cleaner did make the ignition slightly faster, and the low-cost cleaning was easy to perform. But was it worth it? Spending time cleaning is less practical than just replacing the spark plugs—a new set costs only around a hundred yuan and can last 30,000 to 50,000 kilometers worry-free. The cleaning effect is short-lived, as the plugs get dirty again within a month, and improper cleaning could damage the electrodes, causing bigger issues. Nowadays, modern spark plugs are designed with advanced technology and rarely need cleaning. If your engine isn’t running smoothly, check other potential causes instead of relying on cleaning.
