In all aspects of car maintenance, changing engine oil is the most frequent maintenance item, and it is also the most basic maintenance of a car. Generally, I go to the 4S shop for maintenance, saying that I only do the most basic maintenance, that is, I only change the oil. A large barrel of new oil is 4 liters, and a small barrel of oil is 1 liter. Most of the amount of oil required for a car is not a whole number, some add 3.8 liters, some add 4.2 liters, and very few cars add 4 liters just right. Therefore, the vast majority of cars will have a little left, or a large bucket is not enough, and a small bucket will need to be opened, but there will also be a little left.
So what do you do with all this leftover oil? Can the owner take it away and use it next time? Let's talk about the answer first, as long as the storage method is appropriate, it will be no problem to use it next time.
Motor oils have a shelf life and lifespan, and mainstream brands of motor oils can usually last for 4 to 5 years when left unopened. Once opened, its shelf life will be greatly shortened due to contact with air, moisture and dust, and if left at will, it is generally about a year. Once preserved, it can last up to two years. Why does the shelf life become shorter after opening? In fact, it is caused by poor sealing, just like a bottle of beer or soda, if you don't drink it after opening, no matter how you seal and store it, there will be no taste after a day.
What are the substances that affect the deterioration of motor oil? Mainly water, oxygen, dust in the air. The moisture content of a normal motor oil is less than 0.03%. After the engine oil is opened, it will absorb the water vapor in the air when it comes into contact with the air, which will increase its water content, resulting in poor lubricity and viscosity of the oil. The additives in the oil and the oxygen in the air are prone to chemical reactions, especially in the environment exposed to sunlight, which can greatly reduce the antioxidant and cleaning properties of the oil. In addition, the contact between the oil and the dust in the air will also absorb a large amount of dust, which will affect the lubrication effect of the oil, and in severe cases, it will lead to abnormal wear of the engine.
It can be seen that the key to preserving engine oil is to seal it well and avoid contact with water, air and impurities. How to save it? We can seal the bottle mouth with plastic wrap for the remaining engine oil, one layer of plastic wrap is too thin, you can cover a few more layers, increase the thickness, and then tighten the cap. This prevents air and moisture from entering. At the same time, store the oil in a dry, cool, dark place, away from direct sunlight and high temperatures.
Through observation, it is found that everyone can do it by tightening the cap with plastic wrap, but the storage environment often can't do it, and many car owners have been putting it in the trunk. It is important to know that the trunk is not a good place to store engine oil, because the temperature of the trunk is also high after sun exposure. In addition, as the vehicle jolts, the oil will also shake back and forth inside. The temperature of the oil rises, and it keeps shaking in the bottle, and the rate of spoilage will be accelerated. Put it in the garage or in the basement.
Of course, in addition to the storage method, we also need to pay attention to some usage details. First of all, for the next maintenance, do not pour all the oil into the engine, you should keep a part. This is because there may be trace amounts of moisture or impurities at the bottom of the oil drum that has been stored for a long time, and if it is all poured into the engine, the water and impurities will also be poured in, which may affect its performance. Secondly, the next oil change should be added to the last saved one first, and then add a new one, so that what is left each time is the latest oil. Don't keep the rest all the time, and use it together when you've saved up enough once. If you store it for too long, it will deteriorate, and the oil you can store by yourself will not exceed two years.
However, the shelf life of different brands and grades of motor oil is also different, and the higher the grade, the longer the shelf life of fully synthetic motor oil, because its molecular structure is stable and it is not easy to be affected by external influences and fail. It can also be seen from the frequency of oil changes that ordinary mineral oil needs to be replaced after 5,000 kilometers, while if fully synthetic engine oil is used, it can be replaced at 10,000 kilometers. In addition to its good lubricating properties, fully synthetic motor oil also has a longer shelf life.
In short, the remaining engine oil from car maintenance can be put into the next use, so if there is more oil left each time, you can take the initiative to tell the maintenance master that the engine oil is not used up and put it on the car to take away. As long as we take the correct storage method and use details, it is no problem to continue to use it for the next maintenance, so that you can save a barrel of oil money after saving a few times.