Every time we went to change the engine oil, the old engine oil that we put down was very dark. So, do you know why the oil turns black? Is it not of good quality? Every time the oil turns black, it means it needs to be replaced?
* Why Does Motor Oil Turn Black?
To figure this out, we first need to understand the composition of the oil:
There are two main components of motor oil: base oil and additives. Base oil is the main component of lubricating oil, which determines the basic properties of lubricating oil, and additives make up for and improve the shortcomings of base oil performance, which contains detergents and dispersants, which give the oil a certain cleaning ability, which can clean the carbon deposits and oxides inside the engine and dissolve them.
Therefore, it is the added ingredients in the oil that play a cleaning role when the oil turns black. It's the same as when we usually wash dirty clothes, the water turns black, but the clothes get clean. In addition, the oil itself can turn black due to oxidation. When the engine is working, the temperature and pressure are very high, and the oil is constantly circulating in this environment, and it will slowly oxidize and change color.
* Can I continue to use the oil when it turns black?
Some friends are worried: "Every time I change the engine oil, it is very black, has it already deteriorated? It is so dark, I still use it for so long, will it hurt the engine?" In fact, the owner does not need to worry too much.
1. Slightly blackened
The normal color of the engine oil should be yellow or golden yellow, and when it is used for a period of time, it will appear slightly darkened, which is actually normal.
2. There are more blackened parts
At this time, the score situation: it may be caused by inferior engine oil for a while, and the second is caused by wrong driving habits (such as sudden braking, low-speed turning, etc.), and then choose to change the engine oil or correct the driving habits to solve the problem.
3. Deep blackening
This is also a score: some high-end cars because of the use of high-grade engine oil, in order to prevent sludge or soot from forming paint film on the cylinder, so the more oil dispersant, the better the dispersion, the less the paint film will be, but the oil is more likely to turn black. There is no need to change the oil at this time.
Therefore, under normal circumstances, whether the oil needs to be changed and the degree to which its color turns black is not directly related, before the oil change cycle, there is no need to change the oil because the oil is black, and the better the quality of the oil The better the cleaning and dispersibility, the faster it will generally darken.
In general, it is normal for the oil to turn black, and generally the oil will leave a little more life, so don't worry. As long as we follow the maintenance manual and change the oil on time when it's time to change it, there is no big problem.