How Often Should Iridium Spark Plugs Be Replaced?

[NolanDella]

Iridium spark plugs should be replaced every 60,000 to 80,000 kilometers. Under normal maintenance conditions, spark plugs are typically replaced after traveling 40,000 to 60,000 kilometers. However, this may vary depending on the brand and engine type, so it's recommended to follow the guidelines in the user manual. Generally, platinum spark plugs are replaced at 40,000 kilometers, while standard nickel alloy spark plugs are replaced at 20,000 kilometers. Steps for replacing spark plugs: Open the hood and remove the plastic engine cover. Disconnect the high-voltage ignition wires, marking 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 like leaves or dust and clean thoroughly. Insert the new spark plug into the spark plug hole, hand-tighten it a few turns, then use the socket to fully tighten it. Reinstall the high-voltage ignition wires in the correct firing order and reattach the cover.

[ValeriaFitz]

My car uses iridium spark plugs, which lasted six years before needing replacement. These spark plugs are indeed much more durable than standard nickel alloy ones, with manufacturers typically claiming a lifespan of 80,000-100,000 km. However, actual longevity depends on driving habits and road conditions. Since I commute daily on highways, I noticed obvious throttle lag and a 0.5L increase in fuel consumption at around 90,000 km. When the mechanic opened it up, the electrode gap had significantly widened. Here's a tip: if you experience hard cold starts or jerky acceleration, don't just assume it's the throttle body needing cleaning - it might be time for new spark plugs. Prolonged neglect could even damage the ignition coils, which are far more expensive to replace.

[LeHenry]

Last time during maintenance, the 4S shop recommended I replace the spark plugs with iridium ones, claiming they'd last ten years, but in reality, it depends on the actual condition of the car. My experience is: for regular family cars, after five years or 80,000 kilometers, you should check the electrode wear. Pay special attention to modified performance cars—like my neighbor's Civic with a tuned ECU, which started misfiring and shaking at just 40,000 km. When we took the spark plugs out, the center electrodes were completely worn down. Also, engines with oil leaks need earlier replacements. I once worked on an oil-leaking BMW where the spark plug threads were so caked with sludge that any delay might have made them impossible to remove.

[DanielRose]

Having repaired cars for 15 years, I've seen countless cases of failed iridium spark plugs. The most straightforward diagnostic method is to inspect the ceramic body: if the insulator turns yellow or develops cracks, it indicates internal leakage and requires replacement. Last month, I dealt with a Camry with unstable idle when cold - the misfire was caused by cracked spark plugs. Brand selection also matters significantly. Despite both being iridium, Bosch and NGK can differ by two heat range grades. Always match the factory-specified heat range when replacing - switching to higher heat range plugs without authorization may lead to piston melting.