Why Does My Oil Turn Black so Fast? (Should You Be Worried?)

The engine oil isn’t a one-time changing component in your car. Since it runs with the engine, it gets exposed to soot and other particles, wearing it out in time. It’s for this reason that an oil change service exists. However, you may find it problematic to see your oil turning black quickly after the oil change.

So, you may ask: Why does my oil turn black so fast? While an oil change service would remove the dark and worn-out oil in your car’s engine, it can’t seep out all of it. The remnants of the used oil get mixed with the new one. Thus, it results in an immediate darkening of the new oil. Don’t worry, though, as it won’t harm your engine.

Almost all engines would eventually transform the oil into black. For this reason, oils need constant checking and changing to maintain the vehicle’s performance and health. However, it’s also important to note that the oil can turn black soon, but it doesn’t mean you need to change it again.

In this article, we’ll cover everything you need to know about engine oil, mainly how it turns black. This way, you’ll understand your case, if it’s worrisome or not.

Without further ado, let’s get into it!

Why Does My Oil Turn Black so Fast

Why Is My Oil Turning Black?

It’s important to remember that every engine oil turns black at some point, and there’s a reason for it.

If your oil turns black, thick, or just very dark, it indicates exposure to dirt or dust contaminants. Such components appear as the engine runs, and they result in a soot build-up.

Since the oil lubricates the engine as it works, it will always be subject to dark as it runs overtime.

While it’s a regular occurrence, it doesn’t mean you won’t mind it at all.

In general, there’s a limit to how oils can work effectively on a car. Once it starts getting darker and thicker, it lessens the efficiency and can even damage your engine.

For this reason, you must learn to differentiate the color of the oil. This way, you can tell if your car needs an oil change service or not.

Is It Bad If Your Oil Is Black?

As I said earlier, black oil is usually a sign that your car needs its oil changed. However, it’s not the same thing all the time.

For instance, one of the things that cause blackness is the additives. Such things help the engine to run. Thus, your engine oil can’t remain clear due to these additives.

It would be best to keep in mind that a darkening of oil is a sign that your engine works.

The questions would then be how quickly the oil turns black or darkens.

As a general rule of thumb, you can consider your oil alright if it can run 10,000 miles between oil change sessions.

Engine Oil Is Black After a Change – Is It Ok?

The oil change supposedly replaces the dark, black oil with a new, amber, and translucent one. However, you may see the oil is still black after a change. Would it be worrisome?

In general, the changing of oil does replace the blackish one with a clear, amber-colored one. However, take note that the oil change doesn’t altogether remove all the black oil.

At some point, some oil residue will remain in the chamber. Thus, as soon as you place the new oil, the remnants would mix up with it.

With this in mind, always remember that it’s OK if you see your engine oil get dark immediately. 

Why Is My Oil Black After the Oil Change?

As I said earlier, the oil change replaces the oil, black oil, with the new one. Thus, it should give the oil in the engine a fresh appearance from a beginner’s perspective.

However, such an idea isn’t really what is happening.

While the oil change service replaces the dark, black oil, it doesn’t remove it in the chamber. As such, it leaves some remnants of the dark oil.

As the new oil gets poured into it, it gets mixed up with the remnants. As a result, the new oil darkens quickly.

While it may look worrisome, it doesn’t damage the engine. For this reason, you don’t have to worry about it.

black oil

What Color Should Oil Be After an Oil Change?

Since the oil change replaces the old black oil with a new one, take it as a thumb rule that you would see a cleaner oil.

However, don’t get surprised if you don’t see a clean and translucent oil in your dipstick afterward.

The oil change may have replaced the dark oil, but some of its remnants still mixed with the new one. In short, you should see a cleaner oil, but it’s not clean.

How Long Does It Take For Oil to Turn Black?

Due to the remnants of the old oil, an immediate but slight discoloration can happen.

As always, remember that not all oil gets drained in an oil change. Thus, the remnants get mixed with the new one, leading to an immediate darkening.

However, in general, a new oil would likely lose its efficiency and turn darker after a specific mileage or time.

It would depend on the engine’s performance and the kind of oil you use. For this reason, many professionals advise checking the oil color at least once a month.

This way, you will see if your car needs another oil changing service or not.

Why Does Diesel Engine Oil Turn Black Quickly?

Another thing that serves as a factor for oil darkening is the type of engine. In general, vehicles usually run in either diesel or gasoline engines. The former would be more prone to quick oil darkening.

If you’re wondering why diesel engine oil turns black quickly, here’s a short explanation:

Diesel-powered engines have an increased combustion temperature in the cylinders. Such a thing causes the fuel to burn more efficiently.

In such a manner, it also results in reduced exhaust emissions getting released on the tailpipe.

Now, the re-ingested exhaust gases play a role in contaminating the diesel engine oil. Thus, unlike gasoline-powered engines, these turn oil darker quicker.


In general, an oil change service would remove the dark and worn-out oil in your car’s engine. However, it can’t seep out all of it. The remnants of the used oil get to mix with the new one. Thus, it results in an immediate darkening of the new oil.

Such a fact serves as why the engine oil turns dark immediately, even after an oil change. Thus, if you worry about the oil getting darker, it’s not a big deal.

In general, you don’t have to worry as long as your engine doesn’t show any issues, and you regularly change the oil. In the end, the darkening may even seem like a sign that your engine is working efficiently.



Image credits – Canva

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My name is Hank, and I've been in the automotive industry for 27 years. I've been working in my own auto repair shop for the last 13 years, and now I want to help you here, on my blog. Let me know if you have any questions. Read more