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How often should car spark plugs be replaced?

This is a topic that many car owners are particularly concerned about. Some car owners have never changed the spark plugs, they have no idea of it that how important the spark plugs are to the engine.

The type of original spark plugs is different according to different engines, so their replacement kilometers are also different. There are usually three types of spark plugs that match the original vehicles.

Now were going to dismantle the spark plugs of this Korean car.


According to our experience, it should be matched with nickel alloyed spark plugs. Look at the center electrode, its flat.


The price of this type of spark plugs is relatively cheap. It is usually equipped on the vehicles with less than 80,000 yuan (around $12,000) or small SUVs without turbocharger. The suggested replacement cycle of this nickle alloy spark plugs is about 20,000 to 30,000 kilometers.

The second type is platinum spark plug or iridium spark plug, its center electrode is pointed and embedded with platinum or iridium. This type can be used on both supercharged engines and naturally aspirated engines. If it is used on supercharged engines, its service life is 20,000 to 30,000 kilometers. If on naturally aspirated engines, 50,000 to 60,000 kilometers is suggested.


The third type is that the center electrode and the side electrode are both embedded with iridium or platinum, which is called double iridium or double platinum spark plugs. Generally, the quality is much more better, so is the price. It can be used for more than 100,000 kilometers. This kind of spark plugs will much better improve power, reduce fuel consumption and solve shaking.


Besides the kilometers as a criterion to tell whether the spark plug should be replaced,we can also remove the spark plug and check the gap between the two electrodes. The standard  gap is from 1.0 to 1.3 mm. If the gap is over that range, the spark plugs need to be replaced immediately. If not replaced, it will have a great impact on power and fuel consumption.

Remember, the nickel alloyed spark plugs can never been installed in turbocharged cars, because the temperature in the cylinder of turbocharged vehicles is as high as 2500 degrees, and the high temperature resistance of nickel is less than 1400 degrees. If you use nickel alloyed spark plugs, the electrodes will be easily ablated and broken, falling into the cylinder, and cause a great damage to the engine.

The quality of the spark plug directly determines the combustion efficiency and combustion state of the engine. Therefore, when your car reaches the certain kilometers to be replaced, or the engine vibrates, fuel consumption becomes higher, or power becomes weak, you need to check  the spark plugs first.