Oil is a component that cannot be separated from the engine. Oil becomes an obligation on the engine to do its job.
The function of oil as a lubricant does not only lubricate engine components, but ensures engine components can move lightly. So that engine performance can be maximized.
However, the oil will start to get dirty when it is used.
How does oil get dirty? even though the oil is located in a closed engine?
Cause The Oil Becomes Dirty
Even though the oil is located inside the engine that is closed space, that does not mean the engine is free from dirt. This dirt can come from inside the engine itself.
Several things that make oil turn black
1. Carbon deposit
When combustion occurs, it will produce heat, energy and residual gas. The residual gas generated from combustion will stick to the linner. When the oil rinses the linner, this residue will be carried away by the oil so that the oil contains deposit from the results of combustion.
2. Outside Contaminant
If the car operates in a dusty area, it will make the engine oil dirty more easily. That is because contaminant in the air sucked into the engine can be flushed out by the engine oil.
3. Wear and tear
Friction between engine components will cause wear and tear on both components. The debris from this friction will be carried away by engine oil. So that the oil becomes dirty.
I can say, when oil gets dirty and turns black, it is a normal occurrence. In fact, it indicates that the oil is working properly according to its function.
Dirty oil indicates that the oil is able to absorb dirt in engine components.
but how long can oil last? what are the signs that the oil needs to be changed?
To change the oil we only follow the guidelines from the car manufacturer. In fact, the oil is changed when the quality has decrease. One of the characteristics of the decreasing quality of the oil is the oil colored black.
But not all black oil is not suitable for use, some oil that is black is still good as a lubricant.
To be clearer, I will explain the mechanism of how oil can get dirty in the engine.
1. New oil is mixed with the remaining old oil when you change the oil
When changing engine oil, the oil will be drained through the drain bolt. But you need to know, the drained oil is not 100%. there is still oil left in the engine when draining.
That is because oil takes time to get to the bottom, besides that there is some oil that is accommodated in the component basins in the engine.
When we fill new oil, the new oil will mix with the old oil. Even in a small volume, it can change the color of the oil.
So that we often see the oil looks dirty after change.
2. Oil circulates to dirty engine components
Oil will be pumped to all parts of the engine. The amount of oil pressure is influenced by the engine RPM. Components that are lubricated with oil, have scale or dirt that comes from the combustion residue.
The oil will flush the dirt so that the oil turns black.
However, oil is still good for use as a lubricant, because the dirt will be filtered out by the oil filter.
This is the reason why black oil is still suitable as a lubricant.
Apart from the color, the oil molecules can be an indication of whether the oil needs to be changed or not. But we can't check the oil molecules. It is important to understand that the oil molecules will be damaged when exposed to continuous heat.
Usually the oil will become thinner.
This is a sign that the oil needs to be changed.
So in conclusion, the oil becomes dirty, indicating the oil is working well. The higher the engine RPM, the faster the oil gets dirty. If you are driving on congested roads, the oil change interval should be faster than standard.
Because the engine still run when the car is not running, so the engine mileage is farther than the car mileage.