How Long Can Your Motor Oil Last?

motor oil shelf life

As a driver, you should be aware of the importance of appropriate oil changing in your car. There are times when you will plan on storing your motor oil and it is quite normal for you to wonder just long you can store it for.

Bear it at the back of your mind that it is recommended that you store motor oil in a cool, dark place if you want it to have a longer shelf life.

Normally, motor oil should stay in good condition for up to five years depending on some factors. To get the best out of the oil, it is recommended that you stick to the manufacturer’s storage instructions.

It is also very important that you check out the expiry date and once it has expired, you will do yourself a world of good by not using the oil.

You should know that there are different types of motor oils. Examples of the types of motor oil available in the market include conventional motor oil, synthetic motor oil, synthetic blend motor oil, as well as high-mileage motor oil.

Earlier on, we pointed out that there are some factors that influence the shelf life of motor oil and examples of these factors are the composition of the oil as well as the additives in them.

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Factors That Influence The Shelf Life of Motor Oil

Composition of Motor Oil

How long your motor oil lasts for you highly depends on its composition. Let us begin with Synthetic motor oil, which is gotten from petroleum and non-petroleum chemical compounds.

Hydrocarbon molecules spread evenly through the base and this creates an alkali or you could say a base which stays stable whether in very high or very low temperatures.

Also, there is the absence of pollutants such as paraffin wax which is a component of crude oil, and this factor is one of the reasons why synthetic motor oil can stay okay for longer.


Motor oil manufacturers include a lot of additives to their oil products with the aim of making it the best option for your engine and to also give it a longer shelf life.

One of the functions of the additives is to make sure that the oil retains its consistency and is always able to flow freely no matter the temperature, according to the stipulated test standards.

We will now proceed to take a look at some of the additives in motor oil that can make its shelf life longer or otherwise.

Some of the motor oil in the market that have elements such as copper and iron in them tend to have a lower shelf life. The reason for this is that copper and iron function as catalysts and makes oxidation faster.

Motor oil manufacturers include pour point depressants or PPDs in their product in order to prevent the oil from freezing at low temperatures. How this works is that pour point depressants are a kind of polymer, whose function is to prevent the formation of wax crystals and allow the oil to flow freely.

Detergents and dispersants can also be added in the motor oil. This is to inhibit the formation of sludge in the oil. What this does is that it suspends contaminants in the oil and this goes a long way in ensuring that the oil stays clean.

There is also the presence of defoamants to stop the motor oil from frothing or forming bubbles.

Most of the motor oils available in the market have alkaline additives which go a long way in neutralizing the acidic contaminants.

Motor oil manufacturers also include oxidation inhibitors so as to maintain the stability of the oil. There are also rust and corrosion inhibitors and their function is to stop condensation.

There is equally Calcium additives which makes sure that the motor oil gets oxygen. Another function of the Calcium additives is to help slow down the formation of varnish and sludge.

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Other factors that determine shelf life of Motor oil

Apart from the composition of the motor oil and the additives in them, there are other factors that determine how long they can stay for and we are about to discuss them now.

If you want your motor oil to last longer for you, it is highly recommended that you store it in a place with a temperature of between 40 degrees and 85 degrees Fahrenheit.

Harsh temperatures for instance below 0ºF or above 100ºF can distort its stability and can prevent it from properly lubricating the engine. More so, really low temperatures can cause sediments to form in the motor oil.

It is also better to not keep the motor oil in a dusty environment as this can make it to loose quality.

Make sure that you are not exposing the oil to humidity as this can result in its condensation. Moisture when in contact with the additives present in the motor oil can cause insoluble particles to form. More so it can cause sludge to form and make the motor oil conducive for microbes.

Finally, a container of motor oil that has not been opened will last longer.

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How to know a stable and safe to use motor oil

First is to check the expiry date. If the motor oil has not expired then it is okay to be used but you still have to conduct some checks that notwithstanding.

You have to check for its consistency. If you see that the motor oil is sticky and thick, and there is the presence of gel-like or solid particles, then you shouldn’t make use of that oil.

Also if you notice that the additives appear to have been separated from the oil, you shouldn’t use it.

Another thing that you have to also look out for is the color of the oil. Good motor oil should have a clear appearance so if you observe any form of murkiness or haziness in it that is indicative of water contamination. Also if the motor oil has changed from its original color, it could mean that it is no more stable.

Also bear it in mind that even though you followed all the rules on how to properly store motor oil there can still be some changes, so it is best that you conduct some checks before use each time.

The reason for this is that the changes of temperature in your storage space can result in the movement of air in and out of the motor oil container especially if there is space in it not occupied by the oil.

If the temperature gets high, air leaves the container and when the temperature is low, air goes into it. All these affect the state of the oil over time.

Another thing you have to make sure that you do is checking whether your car is compatible with the motor oil that you have as making use of the wrong motor oil in your vehicle can cause damage to your car engine.

Also ensure that the motor oil of your choice meets the standard stipulations and regulations.