How Often Should Iridium Spark Plugs Be Replaced?
4 Answers
Iridium spark plugs should be replaced every 80,000 kilometers, while ordinary spark plugs need replacement every 30,000 kilometers, and platinum spark plugs around 60,000 kilometers. Common faults of spark plugs include: 1. Severe erosion of the spark plug; 2. Deposits on the spark plug. When the owner notices scars or damage at the top of the spark plug, or if the electrodes show signs of melting or erosion, it indicates that the spark plug is already damaged and should be replaced. Spark plugs, commonly known as 'fire nozzles,' function by discharging the pulsed high-voltage electricity delivered by the high-voltage wire, breaking down the air between the two electrodes to generate an electric spark that ignites the mixed gas in the cylinder. They mainly consist of a terminal nut, insulator, terminal stud, center electrode, side electrode, and shell, with the side electrode welded onto the shell.
From my interactions with many car enthusiasts, I've found that iridium spark plug lifespan isn't as rigid as imagined. Official data often claims 80,000 to 100,000 km usage, but this really depends on circumstances. For vehicles frequently driven in urban areas with constant traffic congestion causing repeated engine start-stop cycles, or for drivers who often floor the accelerator, spark plug wear occurs much faster. I once saw a Golf whose electrodes were nearly worn out at just 70,000 km when removed. So don't just focus on mileage - pay attention to symptoms like rough idling, sluggish acceleration, or sudden fuel consumption increases. I recommend having a mechanic inspect them every 20,000-30,000 km. Early replacement is always better than risking broken electrodes damaging ignition coils, which would cost far more to repair.
Based on my years of practical repair experience, iridium spark plugs can easily last up to 100,000 kilometers, but there are prerequisites. First, you must use products from reputable brands—never trust those claiming to be OEM parts that cost just a few dozen yuan. Second, regular inspections are crucial, especially after driving 50,000 to 60,000 kilometers. During each maintenance session, have the mechanic check the ignition gap. Don’t wait until the spark plugs completely fail to address the issue. Just the other day, I repaired a Passat whose owner stubbornly pushed the spark plugs to 130,000 kilometers, resulting in cracked ceramic bodies that scratched the engine cylinder. Additionally, turbocharged models require extra attention. Due to high-temperature and high-pressure conditions, it’s advisable to inspect them earlier, around 60,000 to 80,000 kilometers. The safest approach is to keep a spare spark plug in the car so you can replace it immediately if a cylinder misfire occurs.
Friends using iridium spark plugs should learn to observe their vehicle's condition. When cold starts take noticeably longer, or when climbing hills the throttle feels weak accompanied by slight jerking, it's most likely the spark plugs failing. My car uses Denso iridium-platinum plugs, and these symptoms started appearing at the 90,000-kilometer mark. After timely replacement, the engine sound immediately became much crisper, and fuel consumption dropped from 9.2 to 8.5 liters per 100 km. I especially remind hybrid owners to pay attention - the repeated start-stop cycles place greater stress on spark plugs. Generally, it's recommended to inspect them every five years or 70,000 kilometers - don't blindly believe longevity claims. For modified performance vehicles, maintenance intervals should be halved.
