Does Synthetic Oil Degrade Over Time?(Solved)

Does Synthetic Oil Degrade Over Time?

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Does Synthetic Oil Degrade Over Time?

There are countless debates emanating from synthetic oils. Confusion in equal measure has characterized the synthetic oils’ discussions.

Many people wonder if synthetic oils are better than conventional oils, and they continually ask, does synthetic oil degrade over time?

Yes, Synthetic oils change and degrade over time, although the degradation is not that it’s unusable. Consequently, synthetic oils have better qualities than conventional oils and are rated more superior. they work differently and will certainly change when used over time. However, they can never revert to a state for re-usability.

It would be fair to have the question addressed in a very candid manner.

There is justification for the confusion and the countless debates. Manufacturers have not agreed on a universal definition for synthetic oils.

Some of them define them as chemically formulated oils that lack petroleum as their base. Synthetic oils and convectional oils have glaring differences that also affect their performance.

Read along to get the facts and separate them from the common myths. There is a difference in the chemical buildup of synthetic and conventional oils.

Does Synthetic Oil Degrade Over Time?

As convectional oils are used over time, the chemical composition changes, making it thicken with time and usage. The result is an oil of a lower grade that is usually unusable.

On the other hand, synthetic oils work differently. Synthetic oils will certainly change when used over time. However, they can never revert to a state for re-usability.

Indeed, an old synthetic oil will still function as new convectional oil, although it may be slightly thicker than a new one.

What Makes Synthetic Motor Oil to Degrade Over Time?

Various factors will cause synthetic motor oil to degrade over time. First, the oil may get used.

The use of a vehicle occasion traces of water and hydrocarbons that are known to contaminate the oil.

This is the primary reason that the manufacturer will want you to change the oil every year.

However, this once-in-a-year oil change may not work for all since other factors come to the fore when it comes to the degradation of synthetic motor oils.

Cars used for short distances will not need a long duration to change the oil, like cars used for long distances.

The cars used for local running rarely allow the engine to heat up since they are switched on and off after a very short time.

The engine lacks time to evaporate the water vapor, and this starts to dilute the synthetic oil.

When this happens, sludge and acids will form. This will finally affect the performance of the engine and may even damage it.

On the other hand, the additives that make up the synthetic oils also dictate the degradation of the oil.

As you start to use your car engine, the chemical additives in the oil start degrading. This is a slow process but slowly starts to impact the performance of the engine.

It’s appropriate always to schedule a timely oil change. This should not be determined by your opinion on whether the engine has degraded or not.

If you do not change your engine at appropriate times, you may as well void your warranty. Additionally, the lifespan of your engine will be at risk.

Does Synthetic Oil Degrade Over Time?

Is There Any Difference Between Synthetic And Conventional Oils?

Using your eyes to identify the difference between synthetic and conventional oils will give you the impression that they are the same.

The difference between the two categories of oil is subtle. For instance, their makeup makes for a great distinction between the two.

Look at a conventional 5W-30 motor oil, for instance; at low temperatures, it’s a thick petroleum-based oil but thinned at high temperatures.

This variance within the same oil had to be changed, and manufacturers came up with synthetic oils.

With additives, the oil properties are changed, which reduces its viscosity at lower temperatures.

They also thicken the oil at higher temperatures. New convectional  5W-30 motor oil is not different from its synthetic counterpart in functionality.

Unfortunately, this changes over time since the chemical additives either vaporize.

This returns the oil to its original consistency. Considering synthetic oils, it’s evident that they are designed to match a particular type of multi-grade oil right from the start.

Do Synthetic Oils Last Longer Than Conventional Oils?

Synthetic motor oil lasts longer than conventional oil.

There are long intervals of oil change that you will enjoy using synthetic oils compared to when you are using conventional oils.

However, some manufacturers recommend an oil change 3000 or 5000 miles. Other manufacturers’ recommendations range from 7500 to 20,000 miles.

Additionally, the driving conditions and driving style come into play when considering the intervals for an oil change.

It’s essential to ensure that all recommendations for an oil change in your owner’s manual are followed when your car is under warranty.

This should override the recommendation of oil manufactures. CLICK HERE to check current prices on Amazon Prime.

If you would wish to abandon the use of conventional oils and switch to synthetic oils.

It’s essential to ensure more frequent oil changes as your car engine will probably have deposit buildup and sludge from the conventional oils.

What Advantages Does Synthetic Oil Have Over Conventional Oil?

Considering that the creation of synthetic oils is through the employment of complex processes. They quickly achieve the desired molecular specifications needed for particular applications.

Due to the processes that manufacturers use in synthetic oils, it’s easy for them to eradicate unwanted impurities found in crude oil.

They, therefore, tailor the oil molecules to meet specific demands that come with modern engines.

As a consequence, car owners can enjoy superior levels of protection for their cars. This can scarcely be achieved by conventional oils.

Additionally, there is greater engine protection that is offered by synthetic oils. Engine car parts are known to move at high speeds, maintaining contact with each other.

This can result in the wearing down of the components due to extreme temperatures in the engine.

Those moving parts require a protective element, and synthetic oils are the perfect solution to this.

Synthetic oils will provide this needed protection for longer times.

Another thing that we cannot take for granted is the fact that synthetic oils are cleaner to use.  

Unlike conventional oils, which leave huge deposits and sludge in the engine, synthetic oils leave very few impurities and deposits.

This will ensure a cleaner engine whose performance and lifespan are not impaired.

Synthetic oils (Amazon link)are good at offering the required viscosity at both extremes of temperatures.

These oils enjoy better stability at both high and low temperatures.

Hence your engine will run smoothly. Additionally, synthetic oils offer better turbocharger protection.

If you have a turbocharged engine, it is best to use synthetic oils as opposed to conventional oils.

How Can You Know When Synthetic Oil Expires?

It’s not easy to give a precise answer to this question.

With so many issues related to the expiry of synthetic oils, it would be misleading to give a straightforward response to this concern.

When you consider the longevity of synthetic oils, many factors come to play. Before considering the reuse of synthetic oil, it’s needful to consider several factors.

This is because you need to ensure that the oil has not lost its protective factors required by your engine.

At one time, any driver will have to encounter the need to change their engine oil.

Some drivers will change the engine themselves, while others will go to auto care to have their engine oil changed.

No matter your preferred method of changing your engine oil, you will always encounter some concerns.

One concern that comes to the thoughts of many drivers is whether there is a need to change synthetic motor oils.

When you want to change your oil, you need to be sure that the oil you are using is not expired.

Synthetic oils have a shelf life of about seven years. Many people look at this and prefer to buy their oil in bulk to make a saving.

However, this may not automatically qualify as a good idea since the dating is based on appropriate storage.

If the oil is not stored in ideal situations, it will not last the seven-year period. It is better to buy as much oil as you need for every single oil change.

Since synthetic motor oils have a chemical composition that makes them better, the duration is critical. The chemical composition will not last forever.

The specific additives determine the duration the oil will last. Temperatures storage comes as another factor of great significance in determining how long the oil will last.

How Long Will Synthetic Oil Last After Being Opened?

After changing your car engine oil, you may have some leftovers.

Indeed, your leftovers may accumulate over time to the extent that they can be enough for an oil change.

Generally, the use of these leftovers is safe; but you need to consider some factors.

First, ensure that the dates imprinted on the leftovers are still valid. If you mix leftovers without checking the dates, you may end up contaminating the leftovers.

Additionally, It,s also essential to ensure that the oils were stored well before deciding to use them.

Although the shelf life shown on the containers may be the same, if not stored under the same ideal conditions, they will have different shelf lives.

Storing greatly impacts the shelf life of synthetic oils. It’s essential to note that oils stored in extreme temperatures will have degraded and may not help protect your engine.

Does Synthetic Oil Degrade Over Time?

Again, if the oils are stored in a dusty environment, they may end up being contaminated.

Also, consider that storing the oils for years may have the additives change the oil composition.

Can synthetic motor oil go bad when the bottle is not opened?

From a general perspective, synthetic motor oils will last for many years. However, the duration they last will vary for different brands.

When it comes to extended periods that synthetic motor oils will last, there are different timings from different manufacturers.

For instance, Total gives a maximum of two years while Mobil gives a maximum of five years.

Worth noting is that the extended period will not be effective if the oils are not stored in the ideal climatic conditions and their original containers.

Again, oils are best stored away from direct sunlight. Oil molecules are vulnerable to Ultra Violet rays from the sun. The sun’s UV rays occasion a reaction with the oils.

There is also the likelihood of oxidation which will dictate the formation of acids in oils. This will reduce the life span of synthetic oils in a great manner.

Unopened bottles containing synthetic motor oils whose dates are expired should not be used while changing your engine oil.

Although the oil is not opened, it expires once the shelf life is passed.

When synthetic oils expire, there is an irreversible disintegration of the components. This will be evidenced by the presence of some deposits at the bottom of the bottle.

The best way to deal with such oils is to ensure that they are safely disposed of. Regardless of your shaking, there is no way the deposits can be re-dissolved into the oil.

The best environmental condition to store synthetic oils is in a cool and dry place. As mentioned above, this should be away from direct sunlight.


The debate about conventional and synthetic oils is not about to change anytime soon.

However, it’s needful to note that synthetic oils have many advantages over their conventional counterparts.

They will offer your engine more protection for longer. Ideally, driving needs and styles place different demands on your car engine.

It is needful to note such demands as they should work as a baseline for servicing your car. Regardless of your driving needs, you are better off with synthetic oils.

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