It is said that the most contacted during our daily maintenance is conventional small maintenance.
Many car owners see that the oil released by their cars is black and black, and they feel that the oil life is not good, and it is dirty like this after a year of driving. At this time, the so-called old mage in the auto repair plant will tell the owner with a sad face: the same mileage, good oil is still good to use, and the poor oil will be black, which is to explain that the oil is "too poor grade".
Then I took out a bucket of "high-end oil" that claimed not to be black and recommended it to you, saying that because it had just arrived, it was cheaper to sell to the owner of the car to make a friend.
With tears in his eyes, he made hundreds of dollars, and the owner of the car still foolishly felt that this old mage was professional enough and sincere enough.
But have you ever understood a question, does black oil really mean poor oil quality?
Today, Tai Ge came to talk to the masters, and many people said that the blacker the oil released, the worse the oil, the worse it was.
Oil aging is not due to blackening
Instead, the additive decays and turns black
The cause of this statement lies in the "theory of oil deterioration".
Then according to the objective law, the composition of the oil is the base oil + additives. This is true whether it is mineral oil, semi-synthetic oil or fully synthetic motor oil. And these are just the base oils of the engine oil, of which the types of additives and formulas look almost the same and the actual use is very different.
The main role of the additives in the lubricating oil is to improve and enhance the various properties of the oil, so that the oil has better lubrication, cleaning, cooling, sealing, rust and corrosion, cushioning and shock absorption. The types of additives can be as many as more than ten kinds, according to the needs of the formula to increase and reduce the amount of use to meet the characteristics, that is to say, the more advanced the oil, not only the use of the base oil, the better, the more types of additives, naturally the price and quality will be better.
However, the oil circulates in the engine, and the long-term working conditions of high temperatures of more than 100 degrees are very harsh. The gas composition in the engine crankcase is naturally the source of oxygen aging, and under the action of high temperature, the oil is slowly oxidized. Gradual consumption and denaturation, resulting in a decrease in oil performance, the protection of the engine is also reduced.
In fact, this is a normal oxidation phenomenon, and any oil cannot be used endlessly without reducing performance. Therefore, we need to replace it regularly, and the decline and deterioration of the oil is indeed an objective phenomenon.
So let's move on to the second topic: the darker the oil color, the more thoroughly the oil is oxidized and deteriorated?
Additives often determine the performance orientation of the oil
As we just mentioned above, there are many kinds of additives for motor oils, one of which is called "cleaning dispersant". It is alkaline and can be chemically neutralized with colloids, sludges, etc. in motor oil (most of these dirty things are acidic substances). In the most popular way: it can "wash off" the dirty things such as gum and sludge inside the engine.
It is said that after the dirty things are washed off, the color of the oil does not turn black. This directly shatters the theory of "based on whether the color turns black"! Moreover, the color shades of different brands of new oils are different, and the conditions for fair comparison are lost at the beginning;
It is precisely because of the clean dispersant content of the oil, the cleaning ability is strong and naturally "black fast", and the clean dispersant content of the oil is just the opposite. If you use thousands of kilometers of oil, the color of the release has not changed at all, still crystal clear, which is not normal, it is likely that the cleaning ability of this oil is too poor, resulting in "nothing can not be washed off."
The main cleaning effect of the oil contains a lot more clean dispersant than the main long-lasting lubricating oil, which also affects the "cleaning ability" of lubrication.
If you tell me now that the blacker the oil, the worse it is, then Shell estimates that it will carry a 40-meter knife to check the water meter.
Therefore, many "indigenous methods" on the market for auto repair often lack accuracy. For example, it is also inaccurate to use methods such as checking the feel of the oil and smelling the taste of the oil to identify the state of the oil.