The oily deposits on the flower plug indicate lubricant ingress, while the fragmentation at the insulator's apex may suggest low gasoline octane rating.During vehicle maintenance, special attention should be paid to spark plug condition, as high-performance spark plugs can enhance vehicle power performance.Under normal circumstances, the service life of spark plugs is 15,000 kilometers, while long-life spark plugs do not exceed 30,000 kilometers.However, many car owners frequently encounter various issues with their spark plugs, preventing them from reaching their normal service life.

In fact, spark plugs operate at relatively high temperatures.During normal engine operation, the temperature of the spark plug insulator skirt typically ranges between 500 and 600 degrees Celsius.Both excessively high and low temperatures are detrimental to spark plugs.When spark plug temperature is too low, carbon deposits tend to form on the insulator, eventually causing electrical leakage and resulting in misfire.If the spark plug operates at excessively high temperatures, it may lead to premature ignition and engine detonation.At Chery Automobile Training Camp, staff from the authorized dealership categorized common spark plug failures into two types.One is severe spark plug erosion, and the other is spark plug deposits.

Spark plug ablation

When the vehicle owner notices scars or damage on the top of the spark plug, or observes melting or erosion of the electrodes, it indicates that the spark plug has been damaged and should be replaced immediately.During the replacement process, the vehicle owner can inspect the symptoms of spark plug erosion and color changes.

Symptom 1: Electrode melting with white insulation

Diagnosis: This phenomenon indicates excessively high temperature in the combustion chamber.This may be caused by excessive carbon deposition in the combustion chamber, resulting in reduced valve clearance, which further leads to exhaust valve overheating or malfunctioning of the cooling system.Electrode melting and white insulation discoloration may occur when spark plugs are not tightened to the specified torque.

Symptom 2: Electrode rounding with scar formation on the insulator

Diagnosis: This indicates premature engine ignition, which may be caused by factors such as premature ignition timing, low gasoline octane rating, or excessively high spark plug heat value.

Symptom 3: Fracture at the apex of the insulator

Diagnosis: Generally speaking, detonation combustion is the primary cause of insulator rupture.Premature ignition timing, low octane gasoline, and excessively high combustion chamber temperatures may all lead to engine detonation combustion.

Symptom 4: Gray-black streaks at the top of the insulator

Diagnosis: The appearance of these streaks indicates that the spark plug is leaking air, and the vehicle owner must unconditionally replace it with a new component.