What are the symptoms of aging spark plugs?
2 Answers
Symptoms of aging spark plugs include: difficulty starting the engine, reduced power, excessive exhaust emissions, and increased fuel consumption. Steps to replace spark plugs: Open the hood, lift the plastic engine cover, remove the high-voltage ignition wires, and 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 external debris like leaves or dust and ensure everything is cleaned thoroughly. Place the new spark plug into the spark plug hole, hand-tighten it a few turns, and then use the socket to tighten it further. Reinstall the high-voltage ignition wires in the correct firing order and reattach the cover. Methods to determine if a spark plug is damaged: Remove the spark plug and inspect its appearance. A normal spark plug's insulator skirt and electrodes should appear gray-white, gray-yellow, or light brown. A properly functioning spark plug has a reddish-brown insulator skirt, with an electrode gap between 0.8-0.9mm and no signs of electrode burning. If the spark plug is covered in oil or deposits but is otherwise undamaged, it can be cleaned and reused. If the spark plug is severely damaged—showing signs of blistering, black streaks, cracks, or melted electrodes—identify the cause of the damage, fix the issue, and replace the spark plug. Additionally, if the spark plug appears blackened as if smoked, it indicates the wrong heat range was selected or the air-fuel mixture is too rich, possibly due to oil leakage.
I've personally experienced the troubles caused by aging spark plugs. The car became particularly slow to start, especially in cold weather, requiring multiple attempts before it would fire up, and sometimes it almost didn't start at all. During acceleration, it felt sluggish, with delayed response when pressing the gas pedal, making overtaking difficult. At idle, the vibrations were noticeable, with the entire body shaking, and you could feel the wobble inside the car. Fuel consumption also skyrocketed—previously, a full tank could last 400 kilometers, but now it barely reached 350. In severe cases, there was even a misfire, with the engine shaking violently, almost stalling on the road. I didn’t pay attention at first, but after breaking down halfway, I finally replaced the spark plugs. Now it runs much smoother. I recommend regular checks and replacing them every 40,000 to 50,000 kilometers to avoid these headaches. Don’t wait until small issues turn into big problems before regretting it.
