What Are the Consequences of Not Tightening Spark Plugs Properly?
2 Answers
If spark plugs are not tightened properly, the symptoms include air leakage, engine shaking, and failure to start. When replacing spark plugs, the torque applied should match the required torque for the specific spark plugs being used, as spark plugs of different sizes require different amounts of force. Steps for replacing spark plugs: Open the engine hood, lift the plastic cover of the engine, and remove 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. While removing them, check for any external debris such as leaves or dust, and ensure everything is cleaned thoroughly. Place the new spark plugs into the spark plug holes, hand-tighten them a few turns, and then use the socket to tighten them further. Reinstall the high-voltage ignition wires in the correct firing order, then secure the cover. Spark plug replacement intervals: Under normal maintenance conditions, spark plugs should be replaced every 40,000 to 60,000 kilometers. However, this may vary depending on the brand and engine type, so it's recommended to follow the vehicle's manual. The following standards can be used as a reference for maintenance and replacement: Platinum spark plugs should be replaced every 40,000 kilometers, standard nickel alloy spark plugs every 20,000 kilometers, and iridium spark plugs every 60,000 to 80,000 kilometers.
Last time I changed the spark plugs myself, I didn't tighten them properly. Then when driving, I noticed the engine kept shaking and making unusually loud noises, like there was an air leak. The power dropped significantly, struggling even on uphill roads. Fuel consumption also skyrocketed, burning almost an extra liter per 100 kilometers. After driving like this for a week, I finally went to the repair shop. The mechanic said if left unfixed for long, the spark plugs could get burnt out, or even damage the cylinder head gasket, which would be expensive to repair. He advised always using a torque wrench to tighten them properly instead of going by feel, and to pay extra attention during regular spark plug replacements. Otherwise, breaking down halfway would be a real hassle.
