Can Spark Plugs Still Be Used After Getting Wet?
2 Answers
If the spark plugs get wet during engine washing, as long as the engine starts normally, there will be no impact on the vehicle. Spark plugs are a crucial component of a gasoline engine's ignition system. They introduce high voltage into the combustion chamber and create a spark by jumping the electrode gap, thereby igniting the combustible air-fuel mixture in the cylinder. Spark plugs are installed on the side or top of the engine. In earlier designs, spark plugs were connected to the distributor via ignition cables. However, over the past decade, most car engines have switched to direct connections between the ignition coil and the spark plug. 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. This results in the formation of a discharge channel between the gap, leading to a "breakdown" phenomenon. At this point, the gas becomes a luminous body, known as a "spark." Along with the thermal expansion, a "snapping" sound is also produced. The temperature of this electric spark can reach as high as 2,000–3,000°C, which is sufficient to ignite the air-fuel mixture in the engine's combustion chamber.
I generally do not recommend continuing to use a spark plug after it has been exposed to water. Water can cause a short circuit between the internal electrodes, affecting the ignition performance. Even if the exterior appears dry, moisture may remain in the gaps, leading to corrosion and rust. Prolonged use of a water-damaged spark plug can easily cause engine starting difficulties, shaking, or even stalling. In my repair work, I have seen many cases where car owners tried to save trouble by simply drying the spark plug, only to have the vehicle develop problems again soon after, resulting in additional costs for replacing the ignition coil. To completely avoid risks, it is best to replace the spark plug with a new one to ensure stable engine operation. Additionally, pay attention to maintaining the engine's sealing during regular maintenance, especially when washing the car or during rainy weather to prevent water from splashing in.
