The oily deposits on the flower plugs are the entry of lubricating oil, and the chipping of the top of the insulator may be caused by low gasoline grade. When maintaining a car, pay more attention to the condition of the spark plug. A spark plug with excellent performance can improve the dynamic performance of the vehicle.
Under normal circumstances, the service life of spark plugs is 15,000 kilometers, and the service life of long-lasting spark plugs does not exceed 30,000 kilometers. However, many car owners’ spark plugs often suffer from problems of this kind and fail to reach their normal service life.
Actually, the working temperature of spark plugs is quite high. When the engine is running normally, the temperature of the spark plug insulator skirt is generally maintained between 500 and 600 degrees Celsius. The temperature is too high or too low to affect the spark plug badly. When the temperature of the spark plug is too low, the insulator on the spark plug is easy to deposit carbon, which will eventually cause leakage and cause misfire. If the working temperature of the spark plug is too high, it is easy to cause pre-ignition and engine knock. Common faults are classified into two types. One is that the spark plug is severely ablated, and the other is that the spark plug has deposits.
Spark plug ablation
When the car owner finds that there is a scar or damage on the top of the spark plug, the electrode is melted, or ablated, it all indicates that the spark plug has been destroyed, and the spark plug should be replaced at this time. During the replacement process, the owner can check the symptoms of spark plug ablation and the change of color.
Symptom 1: The electrode melts and the insulator is white
Diagnosis: This phenomenon indicates that the temperature in the combustion chamber is too high. This may be caused by excessive carbon deposits in the combustion chamber, resulting in too small valve clearance, which may further cause overheating of the exhaust valve or poor operation of the cooling device. When the spark plug is not tightened according to the specified torque, the electrode will melt and the insulator will appear white.
Symptom 2: The electrodes become round and the insulator is scarred
Diagnosis: This indicates that the engine burns prematurely, which may be caused by premature ignition time, low gasoline octane number, and high spark plug calorific value.
Symptom 3: The top of the insulator is broken
Diagnosis: Generally speaking, knocking combustion is the main cause of insulator rupture.Premature ignition time, low gasoline octane number, and high temperature in the combustion chamber may all cause the engine to knock and burn.
Symptom 4: Gray-black stripes on the top of the insulator
Diagnosis: The appearance of this streak indicates that the spark plug has leaked, and the owner needs to replace it with a new one unconditionally.
Deposits on the spark plug
Deposits sometimes stick to the tip of the spark plug insulator and the electrode. Car owners should not underestimate this deposit.
In severe cases, this situation may cause the engine to fail to work normally. After cleaning the spark plugs, the vehicle can run normally for a while, but a similar situation will occur again soon. In fact, the presence of deposits on spark plugs is only a superficial phenomenon, which may be a signal of problems with other mechanical parts of the vehicle.
Symptom 1: Oily deposits on the spark plug
Diagnosis: When oily deposits appear on the spark plug, it indicates that the lubricating oil has entered the combustion chamber.If there are only oily deposits on individual spark plugs, it may be caused by damage to the valve stem oil seal. However, if the spark plugs of each cylinder block have this kind of deposits, it means that the cylinders are leaking oil.Generally speaking, when the air filter and the ventilation device are blocked, the cylinder is prone to oil leakage.
Symptom 2: Black deposits on the spark plug
Diagnosis: There are black deposits on the spark plug electrode and inside, which usually indicates that the gas mixture in the cylinder is too thick.The owner can increase the engine speed for a few minutes to burn off the layer of black soot left on the electrode.
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