What Happens If Spark Plugs Are Never Replaced?
4 Answers
Effects of not replacing spark plugs: If spark plugs are damaged, it can directly cause issues such as leakage in the vehicle's ignition system, increased fuel consumption, reduced power, and most importantly, difficulty in ignition, affecting the normal operation of the vehicle. Severe erosion of spark plugs, including scarring at the top, damage, or melting and erosion of electrodes, indicates that the spark plugs are already damaged and should be replaced. Methods to determine if spark plugs are damaged: Remove the spark plugs and observe them to assess their condition based on the following appearance colors. 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, an electrode gap between 0.8-0.9mm, and no signs of electrode burn. If the spark plug is covered with oil or deposits but is not damaged, it can continue to be used after cleaning off the oil and deposits. If the spark plug is severely damaged, with signs such as scarring, black streaks, cracks, or melted electrodes at the top, the cause of the damage should be identified. After troubleshooting, replace the spark plug with a new one. Additionally, if the spark plug appears black as if smoked, it indicates that the wrong heat range was selected or that the air-fuel mixture is too rich, with oil seeping up.
If the spark plugs are not replaced for a long time, the car will become very unpleasant to drive. I've experienced it myself—starting the engine often requires repeatedly turning the key, making the car feel sluggish like an old ox. Acceleration also loses power; even pressing the gas pedal all the way down won’t help it pick up speed, and fuel consumption inexplicably increases, with a full tank running out much faster than usual. Over time, the car is prone to shaking, feeling unstable even when idling at a red light. The most annoying part is the strange noises during startup, like coughing, which could potentially affect the entire ignition system if left unchecked. So, I recommend getting them inspected early. Generally, spark plugs should be replaced every few tens of thousands of kilometers. Always refer to the vehicle manual or consult a professional shop, and don’t delay to avoid spending more money fixing other issues later. A worry-free drive is the key to enjoying the journey.
Neglecting spark plug replacement for extended periods can lead to escalating costs. I've observed many car owners initially saving money by postponing spark plug changes. However, as spark plugs age, their ignition efficiency declines, resulting in incomplete engine combustion. This not only increases fuel consumption but also accelerates carbon buildup inside the engine. In severe cases, it can cause cylinder pressure imbalance and component damage, requiring repairs costing thousands or even tens of thousands – far exceeding the price of new spark plugs. Additionally, degraded vehicle performance reduces resale value. Regular maintenance actually saves money and hassle. My recommendation: replace spark plugs according to manufacturer intervals (typically every 30,000-40,000 km) – don't wait for warning lights. Monitor idle stability; if you notice abnormalities, have a technician inspect immediately. Preventive maintenance always beats costly repairs.
Not replacing spark plugs not only harms the car but also damages the environment. Worn-out spark plugs cause the engine to exceed emission standards, increasing pollutants like carbon monoxide and nitrogen oxides, which pollute the air and affect public health. It's even more dangerous from a safety perspective—ignition failure can lead to engine misfires, causing sudden deceleration at high speeds and potentially resulting in accidents. I've personally witnessed cases where minor issues escalated into major disasters. Checking spark plug wear early and replacing them promptly can reduce these risks, contributing to environmental protection as well.
