What spark plugs are used in the Corolla?
2 Answers
Toyota Corolla uses iridium spark plugs with the model number SC20HR11. Composition of spark plugs: Spark plugs mainly consist of terminal nut, insulator, terminal stud, center electrode, side electrode, and shell. Types of spark plugs: Main types of spark plugs include: standard spark plugs, projected insulator spark plugs, electrode spark plugs, seat spark plugs, pole spark plugs, and surface gap spark plugs. Working principle of spark plugs: Under high voltage, the air between the center electrode and side electrode of a spark plug rapidly ionizes, forming positively charged ions and negatively charged free electrons. When the voltage between electrodes reaches a certain value, the number of ions and electrons in the gas increases like an avalanche, causing the air to lose its insulating properties and forming a discharge channel between the gap, resulting in a "breakdown" phenomenon. At this point, the gas forms a luminous body known as a "spark." Along with thermal expansion, a "crackling" sound is also produced. The temperature of this electric spark can reach 2000-3000°C, which is sufficient to ignite the air-fuel mixture in the engine combustion chamber.
I'm particularly interested in the topic of Corolla's spark plugs! As a common model, the Corolla typically recommends using iridium spark plugs from Denso or NGK, such as the Denso IK20 series or NGK Iridium IX series. These can significantly improve ignition performance, enabling faster starts and lower fuel consumption. I've personally replaced them and noticed a clear improvement in engine response, making the drive smoother. Don't overlook regular maintenance—check or replace them every 60,000 km to avoid engine shaking or sluggish acceleration due to worn spark plugs. Always choose OEM-compatible products, as counterfeit ones may damage the ignition system. During winter when starting is difficult, spark plug condition is crucial, so timely action is important. Overall, while iridium spark plugs are more expensive, their long lifespan and high efficiency make them a worthwhile investment.
