What are the causes of spark plug damage?
4 Answers
The causes of spark plug damage are: 1. Spark plug ceramic insulator cracking; 2. Carbon buildup in the gap; 3. Electrode erosion; 4. Electrode melting. Precautions for removing spark plugs: 1. Clean any debris from the spark plug; 2. Ensure the engine is in a cold state before proceeding; 3. Protect the spark plug installation port after removal to avoid damaging the insulating ceramic; 4. When adjusting the spark plug gap, avoid touching the center electrode. The working principle of a spark plug is: Under the control of the engine, it introduces the high-voltage electricity generated by the ignition coil into the engine cylinder, creating a spark between the spark plug electrode gaps to ignite the air-fuel mixture, enabling the engine to operate normally.
With over a decade of experience in car repair, the most common issues I've encountered are spark plug carbon buildup and erosion. When an engine burns oil, the oil can enter the combustion chamber, forming black carbon deposits that clog the electrodes. Some car owners opt for cheap, low-quality gasoline, which accelerates the formation of gum deposits. Another issue is the change in electrode gap—maintenance manuals typically specify a 0.8mm gap, but prolonged use can widen it to 1.2mm. The most dangerous scenario is electrode melting, often seen in modified cars where the ignition coil voltage is set too high, causing the electrodes to burn through. When replacing spark plugs, don’t just judge by appearance—I once encountered a cracked plug that was completely invisible to the naked eye. It’s recommended to inspect them every 20,000-30,000 km, and even sooner for turbocharged vehicles.
This little thing is the most easily overlooked in our daily driving. Last week, my car had acceleration stuttering, and the mechanic pulled out all four spark plugs, which were completely blackened. The reason is quite simple: daily commutes of just three kilometers are too short, the engine doesn't warm up properly before shutting off, leading to incomplete fuel combustion and carbon buildup on the electrodes. If you frequently drive on highways, the electrodes would instead turn white from overheating. You can judge the issue by the color: brown is healthy, black indicates carbon buildup, and white means overheating. Nowadays, many direct-injection cars require double iridium spark plugs. My neighbor insisted on installing ordinary nickel alloy ones, and the electrodes melted after just six months. Actually, the safest way is to unscrew and inspect them regularly. The tools for removal and installation only cost twenty bucks.
Spark plug lifespan is tied to three factors: heat range matching, material grade, and manufacturing precision. Last time I compared OEM Japanese and German parts, the ceramic insulator length differed by 2mm - directly affecting heat dissipation efficiency. Iridium-platinum electrodes theoretically last 100,000km, but inferior products with poorly welded side electrodes may lose their tips during operation. Cooling system issues also impact them - when coolant temperature rises excessively, cylinder temperatures spike, causing nickel alloy electrodes to deform. The strangest case I've seen was a high-pressure car wash jet directly hitting the ignition coil, allowing water infiltration that cracked the ceramic insulator.
