How to Choose Spark Plugs?
2 Answers
Intuitively, the selection of spark plug material should be based on the ignition coil. For example, when using an ignition coil with four cylinder wires, the preferred spark plug material is not gold platinum but nickel alloy. If the vehicle uses individual coils without cylinder wires, the minimum material required must be enhanced platinum or even iridium. How to Determine the Quality of Spark Plugs: Remove the spark plug and observe its condition based on the following appearance colors. A normal spark plug has an insulator skirt 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 plug is contaminated 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 blistering at the top, black streaks, cracks, or melted electrodes, 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 creeping up.
Choosing spark plugs might seem simple, but it's actually about the heart of your car. As a veteran driver with nearly 20 years of experience, I’ve learned that the first step is to check the manual. Every car has a specified model—don’t mess around. Engine compatibility is key. For naturally aspirated engines, standard heat range copper-core plugs are reliable and cost-effective. Turbocharged engines, however, require platinum or iridium plugs for faster heat dissipation, high-temperature resistance, and stable performance. Don’t just chase new brands—stick with trusted manufacturers like NGK or Bosch. Checking the electrode gap is also crucial; 0.7 to 1.0 mm is ideal, and a simple caliper measurement will do. If you frequently drive long distances, opt for long-life materials to reduce replacement frequency. I’ve tried iridium plugs—they’re pricier but still perform flawlessly even after 20,000 km. Remember, if the model, heat range, or material doesn’t match, your engine might stall or guzzle fuel. During regular maintenance, always inspect the spark plugs and replace them early to avoid roadside breakdowns.
