Can You Still Drive with One Bad Spark Plug?
3 Answers
You can still drive with one bad spark plug, but only for a short period. Prolonged failure to replace it may easily lead to malfunctions and exacerbate engine damage or even total failure. A damaged spark plug can directly cause issues such as ignition system leakage, increased fuel consumption, and reduced power output. The most significant problem is difficulty in ignition, which affects the normal operation of the vehicle. Severe spark plug erosion—evidenced by scarring, damage, or melted electrodes at the top—indicates that the spark plug is ruined and should be replaced. Spark plug replacement interval: Under normal maintenance conditions, spark plugs should be replaced every 40,000 to 60,000 kilometers. However, this may vary depending on the brand and engine type, so it's advisable to follow the owner's manual. Typically, platinum spark plugs should be replaced at 40,000 kilometers, ordinary nickel alloy spark plugs at 20,000 kilometers, and iridium spark plugs at 60,000 to 80,000 kilometers. How spark plugs work: The spark plug's ground electrode is connected to the metal shell, which is threaded into the engine block via the cylinder head. The insulator primarily serves to isolate the metal shell from the central electrode. The terminal nut is the part of the spark plug that contacts the high-voltage coil. When current passes through the terminal nut and the central electrode, it ionizes the medium between the central electrode and the ground electrode, generating a spark to ignite the air-fuel mixture in the cylinder.
Can you still drive with one bad spark plug? I'd say yes, but I really don't recommend driving for too long. The car might feel like the engine is vibrating heavily, and acceleration could be as slow as a snail crawling, because the faulty spark plug isn't igniting properly, causing that cylinder to stop working and resulting in unbalanced power output. While driving, fuel consumption is likely to skyrocket, not only wasting money but also potentially causing chain reactions if prolonged, such as clogging the catalytic converter in the exhaust pipe, doubling the repair costs. Safety-wise, although it won't break down immediately, poor handling can easily lead to fatigue driving risks. It's best to quickly head to a repair shop and replace the spark plug—parts are cheap and the job is quick, saving you from bigger troubles down the line. Also, remember to regularly check spark plugs during routine maintenance; they should be replaced every few tens of thousands of kilometers—don't wait until they fail.
Last time one of my car's spark plugs failed, I still drove to the supermarket to buy something. I just felt the car shaking a bit and lacking power when accelerating, but it was okay for short-distance emergency driving. Definitely don't drive long distances or on highways, as the engine vibration would be severe and could damage the cylinders or gaskets, making repairs much more troublesome. The spark plug's function is to ignite the fuel, and if one fails, it's like losing a helper, reducing overall efficiency. It's recommended to replace it as soon as possible. A new spark plug doesn't cost much, so don't skimp on this small expense. Usually, pay more attention to the engine sound; if there's any unusual noise, get it checked. Maintaining your car well ensures peace of mind and saves trouble.
