Why Engine Oil Becomes Black? Learn the Truth

Upon pouring your new oil into your motor, you may notice that the color is a bit gold, but a week later, you realize that the oil doesn’t have a fresh look as before because the color have been changed over time.

It might be a case where you have notice that the color is black. But, why does engine oil becomes black? You may be confused at this point and wondering if it is safe for your car or not.

The truth is that it is very normal for oils to turn darker over time as it become worn out due to soot and other particle deposits. This is why you should take the time out to get your engine oil replaced over a period of time.

Why Engine Oil Becomes Black?

Why Engine Oil Becomes Black

The reason behind engine oil turning black has a lot to do with its exposure to dirt and dust contaminants. This usually leads to a soot buildup. At this point, the fuel injection system tend to generate soot and eventually lead the new and clean oils to unwanted conditions of becoming darker.

Here is several seasons why your engine oil is black after an oil change:

Heat Cycles

Heat is actually the main culprit behind your oil turning black.

The thing is that when you drive the car to your destination the operating temperatures will be in the range of 90 to 104 degrees and this surely heats the motor oil. However, when you park the car, it will then cool down.

The cycle will eventually continue as you move from one location to another. Over time some unavoidable additives will make it way in and darken the heat. Also, the dark colored oils tend to built up by normal oxidation when oxygen molecules combine with the molecules and break the chemical stream.

This chemistry is pretty much the same as oxygen makes iron rust. Eventually this oxidation happens because of the high heat.

Deposits Might Be The Issue

It’s safe to say that some deposits have been found on some engine parts and there’s no doubt that your engine oil actually reaches all parts of your vehicle during operation.

What usually happens is that the black color in carbon deposits will then transfer to the fluid causing it to turn black.

You may notice this issue if it’s a case where your engine has buildups inside. So, having a regular is superb as it help to prevent deposit and black oil in your car.

Soot Causes Engine Oil to Turn Black

There is a difference between heat cycle and soot and the reason for this is because heat cycle will causes your engine oil to become dark, while soot will cause it to turn black.

Most people actually think that soot buildup has to do with diesel engine only, but it’s safe to say that gasoline also produces soot.

Soot is known to be formed by insufficient combustion. The particles are extremely small and can only be count in microns, so you don’t have to worry much about your engine being worn-out.

It is said that soot particles tend to come with larger contamination. In order to avoid these harmful effects, you will need to use s bypass filtration system which will help to track contaminants down to micron.