How to Determine if Spark Plugs Need Replacement?
2 Answers
Methods to determine if spark plugs need replacement: Remove the spark plugs and observe their appearance color to assess their condition. Normal spark plugs have insulator skirts and electrodes that 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 burn. If the spark plugs are oily or have deposits but are not damaged, they can continue to be used after cleaning off the oil and deposits. If the spark plugs are severely damaged, showing signs such as blistering at the top, black streaks, cracks, or melted electrodes, the cause of the damage should be identified. After troubleshooting, replace the spark plugs with new ones. Additionally, if the spark plugs appear black as if smoked, it indicates the wrong heat range was selected or the air-fuel mixture is too rich, with oil creeping up. Damaged spark plugs can directly cause issues such as electrical leakage in the vehicle's ignition system, increased fuel consumption, reduced power, and most importantly, difficulty in ignition, affecting the vehicle's normal operation. Severe erosion of spark plugs, including blistering, damage, or melted and eroded electrodes, indicates that the spark plugs are ruined and should be replaced.
I've found that determining whether to replace spark plugs mainly depends on how the car performs. If it's particularly difficult to start, requiring multiple attempts before the engine fires up, or if the engine shakes while driving and the steering wheel vibrates at idle, there's an 80% chance the spark plugs are failing. Power will also weaken, struggling uphill like being out of breath, and acceleration won't feel as sharp as usual. Fuel consumption will increase too, with the gas tank emptying faster, costing you more money unnecessarily. Worn spark plugs can also damage other components like ignition coils, leading to even costlier repairs. Remember, spark plugs should generally be checked every 30,000 to 50,000 kilometers, and going beyond this mileage without replacement carries greater risks. Once, after driving over 50,000 kilometers, replacing the spark plugs made the car run as smoothly as new, with improved fuel efficiency. Addressing these symptoms promptly is the safest approach—don't wait until you're stranded on the roadside to regret it.
