What to Pay Attention to Before Changing Engine Oil

[DeJaxson]

When changing the engine oil of a car, it is important to pay attention to the draining time, which indicates the thoroughness of the oil change. The lubrication system of a four-stroke internal combustion engine is very complex. During operation, the oil pump draws oil from the crankcase oil pan and delivers it through intricate pipelines to achieve pressure lubrication and spray (splash) lubrication at various parts of the engine. Depending on the structure, some car engines have separate lubrication systems for the transmission and clutch. The oil temperature in the crankcase typically ranges between 75°C and 91°C. Key Point 1: After a period of normal operation, the amount of oil stored in the oil pan will always decrease to some extent. Even after the engine is turned off, some oil remains in the oil passages, and this oil slowly flows back into the crankcase (oil storage tank) under gravity. Therefore, when changing the oil, it is necessary to wait for a longer period; otherwise, the oil cannot be completely drained by gravity. Key Point 2: If too much used oil remains Mixing this oil with the newly added lubricant will significantly shorten the service life of the oil. Oil filter replacement cycle: It is recommended to replace the oil filter every 5,000 to 10,000 kilometers to ensure the cleanliness of the oil passages. The engine is equipped with an oil filter in the lubrication system. Many car repair shops, to save time, will lift the car and start draining the oil immediately, then tighten the drain plug and replace the filter, which increases the amount of residual oil. Gravity oil changes are inherently not very thorough, so attention to detail is always necessary during the oil change process.