Does Motor Oil Go Bad?

Does Motor Oil Go Bad

Motor oil is the most crucial fluid for your vehicle to function effectively. It not only prevents damage to your engine but also saves you from a lot of costly repairs. However, as a new car owner, you might be curious to know, does motor oil go bad?

Motor oil does go bad after a certain period. It has a shelf life of around 5 years if it has not been opened. But it is preferable to utilize the oil within a year of opening the bottle. Otherwise, the oil might go bad even before the expiration date ends.

Well, it is not as simple as only checking the expiration date to know if the motor oil has gone bad.

So, in this article, I will discuss how you can identify if your motor oil has gone bad or not, along with some other information that you might find helpful.


How Long Does Motor Oil Last?

Generally, motor oil lasts for up to 5 years. However, the exact lifespan of motor oil is difficult to predict because it is dependent on a variety of factors.

Well, the oil type, the method of storage, the rate of exposure, etc., will determine the longevity of your motor oil. It is possible that once the motor oil is exposed to the influencing components, it will begin to degrade quickly.

Moreover, conventional oil is less processed and has a shorter shelf life. Synthetic oil, on the other hand, contains artificial compounds that work well at higher temperatures. It also indicates that they are more long-lasting than regular engine oil.

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Now, let’s discuss the lifespan of motor oil more specifically for your convenience:

Sealed Bottle of Motor Oil

Sealed motor oil will, in most cases, endure for a long period since it’s in a closed container. If you don’t open the bottle, motor oil remains viable in the container till it expires.

Thus, it will allow you roughly two to five years before the unopened oil becomes unsafe to use.

So, it is best not to open the oil bottle unless it is necessary. Fresh oil, however, would degrade with time, losing the oil additive characteristics. And, it will reduce the oil’s useful life.

Opened Bottle of Motor Oil

Although the motor oil bottle comes with an expiration date of 2 to 5 years, it is primarily for unopened oil. After opening the container of motor oil, it begins to lose its potency. You must use the leftover motor oil within one year of opening.

Regardless of the type of oil you use, dust and humidity would taint the oil once you open the bottle. It can decrease the lubricant quality of the oil and the engine’s ultimate fuel efficiency.

A half-empty container of motor oil is also prone to oxidation causing the oil’s viscosity to rise. As a result, the oxidation process would form sediments and sludge.

Old Motor Oil Left in Your Vehicle’s Engine

Well, if you use your car regularly, you won’t have to worry about whether your motor oil will go bad or not. However, remember to drain your old motor oil completely if you are not using your vehicle for one month or more.

The engine’s mechanical motion causes increased temperature, which can cause the oil to thicken with time. As the motor oil flows, it becomes more susceptible to contamination by soot or microscopic metal slivers.

So, like an open bottle of motor oil, when you keep it in the engine for an extended period it will oxidize.

Furthermore, oxidation can even result in the creation of acids in your engine. It might cause different parts of your vehicle to corrode.


Can You Use Expired Motor Oil?

It would be best if you don’t use expired motor oil since it might harm the engine of your vehicle. Well, using expired motor oil won’t necessarily result in irreparable damage to your car. But you might begin to notice early signs of deterioration from your engine.

Motor oil that is past its expiration date might not be quite as effective as new oil and may cause harm to the engine parts. Furthermore, it might cause issues such as acid accumulation, which will ultimately cause corrosion.

Well, expired motor oil begins to lose its effectiveness. So, the engine parts will not be adequately lubricated when you use them. As a result, components might grind with each other or stop functioning at the pace your car requires.

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Moreover, motor oil also helps to keep the temperature of the engine in check. So, if you use old motor oil, your engine might overheat more quickly.

Additionally, most vehicle companies include several years of maintenance coverage. However, some warranties have requirements attached to them, such as oil changes and regular maintenance.

So, if your vehicle suffers damage as a result of your failure to maintain it according to the manufacturer’s instructions, the company might void your warranty. And if it happens, you will have to spend loads of money on maintenance and repairs in the future.

That’s why using expired motor oil is not a good idea.

I would recommend you dispose of the motor oil when it expires. It will help you to avoid more damage to the engine components and the overall fuel performance of your car engine.


How to Know If Your Motor Oil Has Gone Bad

You can easily figure out whether your motor oil has gone bad or not by checking the expiry date written on the bottle or container. Besides, you can also know the motor oil has gone bad by analyzing its color, consistency, and so on.

The following are some of the ways to know if your motor oil has gone bad:

Expiration Date

First of all, check to see whether the motor oil bottle has an expiry date or not. It is the simplest way to know if you can use the motor oil in your vehicle.

As I have already mentioned, the majority of standard oil brands have a 5-year shelf life. However, synthetic oil might have a lifespan of 7 to 8 years, or possibly longer.

If you can’t identify the expiration date, be sure to finish any unopened or opened motor oil bottles within 2 to 5 years of the manufacture date.

Furthermore, even if your unopened oil appears to be in good condition but the expiration date is over, it is best not to use it.

When you know the motor oil has passed 5 years, you must get rid of it. Otherwise, it might damage your vehicle and its parts.

Sediment Deposits

Sediment deposits may form at the container’s bottom if the motor oil has been resting for a certain period. Such deposits are caused by the oil’s additives, which are used to keep the oil at the proper thickness or viscosity.

When this happens, you must replace the oil rather than use it. Keep in mind that the particles inside the oil won’t be redissolved by simply shaking the bottle.


Another excellent clue to look out for is the oil’s consistency. Motor oil is normally smooth, thin, and liquid. Besides, it must feel slick when you touch it.

On the contrary, if your motor oil seems to be overly firm or dense, or has taken on a slime-like appearance, it has most likely gone bad. The reason might be moisture, resulting in the production of sludge.


Well, you can also inspect the oil’s color when you are confused about the expiration date or the date of purchase. The color of motor oil must be light brownish and transparent.

If the oil has become darker or hazy in color, it has most certainly gone bad. Black or dark-colored oil can imply oxidation, whereas milkiness or haziness might indicate water or soil contamination.

Generally, dust accumulates in opened bottles of motor oil, causing them to discolor. No matter if the discoloration is because of oxidation or dirt, the oil is no longer suitable to use.

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How to Store Your Motor Oil After Opening the Bottle?

There is a high risk of your motor oil going bad quickly after you open the bottle. So, you must store it properly. After opening the bottle, you have to store it in a dry area, within a consistent temperature, and in its actual container.

Here are a few tips for storing your motor oil to ensure its longevity:

It is best to store the motor oil bottle in a dry location. Extra moisture in the oil would lessen its viscosity, which will make it less efficient at lubricating the engine. Keeping an open bottle in a dry place would prevent moisture contamination.

It is a bad idea to transfer the motor oil to a new container or bottle since it can expose it to dirt or dust. So, you should keep the oil in the original container to ensure its long life.

Temperature fluctuations and high temperatures might lead the oil to degrade and change its viscosity. So, store your motor oil at a specific or consistent temperature if possible.




It is necessary to use the right motor oil to ensure your engine works perfectly. By now, you’ve got your answer to the question, “Does motor oil go bad?” So, always check if your motor oil is in a good condition before using it in your car.

Thanks for reading through. Hopefully, you’ve found this article helpful. Take care!

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