What to Pay Attention to When Replacing Spark Plugs?
2 Answers
Precautions for spark plug replacement: When removing the high-voltage ignition wires, mark each cylinder's position to avoid confusion. Use a spark plug socket to remove the spark plugs one by one. During removal, check for external debris such as leaves or dust and ensure thorough cleaning. Methods to determine if a spark plug is damaged: Remove the spark plug and inspect its appearance to assess its condition. A normal spark plug's insulator skirt and electrodes should appear grayish-white, grayish-yellow, or light brown. A properly functioning spark plug has a reddish-brown insulator skirt, an electrode gap between 0.8-0.9mm, and no signs of electrode burn. If the spark plug is contaminated with oil or deposits but remains undamaged, clean off the oil and deposits before reuse. If the spark plug is severely damaged—showing signs of blistering, black streaks, cracks, or melted electrodes—identify the cause of the damage, resolve the issue, and replace the spark plug. Additionally, if the spark plug appears blackened as if smoked, it indicates incorrect heat range selection, a rich air-fuel mixture, or oil leakage.
My neighbor Lao Wang learned the hard way when he changed his spark plugs last time, and now he’s sharing the pitfalls to avoid. Before disassembly, always disconnect the negative terminal of the battery—this safety rule is a must. Having a dedicated spark plug socket and torque wrench is crucial; Lao Wang took a shortcut with a regular wrench and cracked the ceramic shell. The most important thing is to buy the correct model—last time, my car got mismatched heat-range plugs, causing it to shake like a disco during cold starts. When removing old spark plugs, replace them one by one to avoid debris falling into the cylinder, and clean the electrode carbon buildup while you’re at it for smoother operation. Don’t forget to apply anti-seize compound when tightening—Lao Wang said his old plugs rusted solid in the holes, costing him 800 yuan to have a mechanic fix it. Also, remember to apply dielectric grease; skipping this step last time caused unstable idling, and the repair shop charged him for unnecessary diagnostics.
