Where is the spark plug located in a car?
2 Answers
Spark plugs are installed on the side or top of the engine. In earlier models, spark plugs were connected to the distributor via ignition cables, but over the past decade or so, most passenger car engines have switched to a design where the ignition coil is directly connected to the spark plug. How spark plugs work: The ground electrode of the spark plug is connected to the metal shell, which is in turn threaded into the engine block via the cylinder head. The insulator primarily serves to isolate the metal shell from the center 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 center electrode, it ionizes the medium between the center electrode and the ground electrode, creating a spark that ignites the air-fuel mixture in the cylinder. Spark plug replacement intervals: Under normal maintenance conditions, spark plugs should be replaced every 40,000 to 60,000 kilometers. However, this can vary depending on the brand and engine type, so it's recommended to follow the owner's manual. Here are some general guidelines for replacement: Platinum spark plugs should be replaced at 40,000 km, standard nickel alloy spark plugs at 20,000 km, and iridium spark plugs at 60,000-80,000 km.
When I first tried to locate the spark plugs, I was a bit confused. Opening the car's hood, the jumble of metal parts and pipes left me unsure where to start. Later, after checking the manual, I learned that the spark plugs are located on the cylinder head cover of the engine. Specifically, there's one at the top of each cylinder, connected to the ignition coils via wires. Their position is usually at the top section of the engine—for example, in my family car, there are four spark plugs lined up in a row, hidden beneath a plastic protective cover. To access them, you first need to unscrew a few bolts and remove the cover. Some cars, like rear-wheel-drive models with compact engines, may have them positioned slightly further back, but the layout is generally similar. When replacing spark plugs, it's important to ensure the area is free of oil or dirt, as this can affect ignition efficiency. For routine maintenance, I recommend regularly checking their position to prevent loosening and potential failures. After each replacement, the car noticeably starts more smoothly. Though the location might seem simple, understanding it well can save you a lot on repair costs.
