Does Motor Oil Go Bad? Shelf Life For Motor Oil Explained

What is Motor Oil?

Motor oil has a long history since its creation by a physician named Dr. John Ellis in 1866. founder of Valvoline. Motor oil was further popularized by Henry Ford and his auto industry. Historically motor oil did the same thing that it does today.

Vintage oil was a simple mixture of base oil and specific additives. Its purpose, like today was used to keep engine parts lubricated reduced friction, clean and cool engine parts.

Modern motor oil helps to prevent deposits from forming on internal engine components. Additionally, motor oil increases the efficiency of engine fuel, helps the engine remain cool, helps to protect the emission system, and much more.

As vital as motor oil is to any engine part, does motor oil expire? If it does, how does motor oil expire, how does oil expire in the engine, and how to check if your vehicle’s motor is about to expire?

does motor oil expire

Motor Oil Additives

The healthy functions of your car’s engine involve motor oil. Motor oil is highly valued at racetracks simply because internal combustion engines are a complex function of high speeds in a small engine area of each car.

Motor oil prevents the engine’s metal parts systems from touching each other. Just get to know your car and use the manufacturer’s suggestion on the type of motor oil that is best for your brand of car to keep it functioning smoothly.

Manufacturers of modern-day motor oil. especially synthetic motor oil places various types of compounds to its mixture so that it can best protect the engine and allow your engine the quality it needs to run longer.

These additives ensure that your motor oil keeps its consistency and viscosity. In other words, it must freely flow at all temperatures within the required test standards.

A less than perfect shelf life occurs in motor oil brands that contain elements like copper and iron. These elements contribute to increasing oxidation (when oxygen interacts with other elements like metal causing rust) and other catalyst features.

Additives like a PPD depressant formula helps to keep the motor oil from freezing when temperatures begin to drop very low. PPD additives are designed to stop the formation of wax crystals, allowing the motor oil to flow smoothly and quickly.

Detergent infused additives are designed to keep sludge at bay and keep the oil running clean. Other motor oil additives include alkaline that naturally neutralizes any acidic environment.

Calcium infused additives encourages the right amount of oxygen to enter the engine. Also, an antifoam additive compound is added to protect the motor oil from forming harmful air bubbles and causing cross-contamination within the oil’s chemical makeup.

Does Motor Oil Expire?

Motor oil products on display shelves inside a store
Motor oil products on display shelves inside a store.

Motor oil is a petroleum product. Petroleum products do turn because of their chemical reactions to various elements like oxygen, air. light, water, and heat

Even with these variants, motor oil can be stored and remain in good condition based on keeping an unopened and well-sealed motor oil can or bottle on the shelf for a couple of years or as long as five years.

No matter what vehicle you are operating, it is common knowledge that its oil needs to be changed. But how long can we keep motor oil. what is its shelf life? The consensus among motor oil manufacturers and car mechanics is that conventional oil to remain effective can last between 3 to 5 years.

Does motor oil expire – yes It can. But there are several factors that go into answering this question. To being with, have you noticed that your motor oil container features an expiration date? Motor oil manufacturers set their own expiry times.

Expert Tip: Some motor oil manufacturers give an expiration of 3 years, while other brands may say 5 years. Therefore, yes. motor oil does expire in a sense.

The consistency and chemical makeup of motor oil loses its viscosity consistency after a certain period of time; thus, it will not keep your vehicle’s engine operating and lubricated efficiently.

The stability of motor oil is dependent on different factors, especially in how it is stored. Motor oils vary in compensation. There is synthetic, synthetic blend, high-mileage and conventional motor oil.

Each of the motor oil compositions and the additives used in them affects how well they work within the engine after sitting around or sitting inside a non-running vehicle. Additionally, how the oil is stored also factors into its competency within an engine.

Just in case you are holding onto old cans or bottles of motor oil, it is highly recommended that you properly dispose of them. (Take the motor oil to a local auto shop for disposal). Attempting to use expired motor oil will only result in serious damage to your engine.

Remember that car technology is ever-evolving and constantly advancing. What was advanced motor oil a few years ago. can quickly become obsolete today. Simple motor oils can have a longer shelf life than the more complex formulas.

How Does Motor Oil Expire?

Row of motor oil bottles
A row of motor oil bottles.

Motor oil manufacturers advise keeping the oil at an optimal temperature of between 40* and 85* Fahrenheit when being stored.

Any higher temperatures above or too far below these suggested temps will affect the efficiency and stability of the motor oil because sediments can form within its chemical makeup.

Simply stated, modern car engines are running hotter than vehicles performed just 8 years ago. with temperatures up to 235 Fahrenheit. Also, if you use your vehicle to attach a hitch to it. then your temperature gauge will rise, thus working faster and harder.

The rate of oxidation for oil doubles for every 18 F increase in temperature. The expiration of motor oil is also affected in how it is stored.

Dust and humidity will cause condensation in the motor oil. Sludge from too high temperatures will also form creating an environment of harmful microbes that will clog your engine.

Motor oil when left unopened or when it is sealed tightly will remain stable for a long period of time. It is only when the motor oil is disturbed constantly allowing air to enter and exit from the oil’s container does this affect the additives.

Air moving in and out of motor oil on a shelf will result in the oil additives degenerating and becoming contaminated. This occurs because if your small cans or bottles of motor oil are stored in a room that could feature hot or high temperatures, air will naturally escape from the containers.

Air naturally escapes from stored containers causing condensation within the oil soluble which will only get transferred into the engine.

Another factor affecting how motor oil expires is in its fuel dilution. When fuel gets into and travels down to the piston rings, this will also contaminate the motor oil. causing it to lose viscosity.

If your daily drive is only around town or for short trips, this does not allow the motor oil to reach its circulating normal operating temperature.

In other words, short-duration car trips can be a problem. Why? Because the fuel does not have time to properly work its way through the positive crankcase ventilation system (PVC). Your car’s crankcase is what holes your motor oil. Its purpose is to produce gases when the engine burns its fuel.

Consequently, extended driving usage like long road trips increases the temperature of the engine system. Also, the high temperature also will degrade your motor oil and affect your fuel dilution more quickly than normal.

Man refilling motor oil on car engine
Man refilling motor oil on car engine.

Remember to change your oil before and after a long trip as to ensure the health of your engine allowing the motor oil to retain its lubricating prowess. Too much fuel dilution is the cause of sludge and rusts causing the motor oil’s effectiveness to become expired.

How To Check If Your Motor Oil Is Expired

Now that we’ve discussed what engine oil is. its additives, expiration of motor oil. and how motor oil expires, let’s talk about how you can tell if your motor oil has expired, thus requiring you to change it.

Yes, there are give-away signs to help you identify if your motor oil has expired. Let’s look at some instant signs:

  • Modern cars will tell you if your motor oil has expired. The check engine or oil change light will come on automatically.
  • The engine will emit noise as in ticking or knocking.
  • The oil will look dark and dirty.
  • Bad oil will have an odorous bad smell to it.
How To Check If Your Motor Oil Is Expired
How To Check If Your Motor Oil Is Expired.

The exhaust smoke will not look light and clear. If you see some smoke that has a blueish tint this means that motor oil has leaked into the engine, and it is being burned along with the gasoline or fuel.

If you notice any combination of these warning signs, it is definitely time to schedule an oil change to help protect your engine and to keep it from becoming expensively damaged.

Expert Tip: Just a quick note here: Black oil does not mean bad oil. Oil color discoloration is sometimes a natural byproduct of heat and soot particles, which are too small to cause harm to your engine.

Don’t make any engine mistakes, so just to make sure, have an oil checkup performed to fully reveal the condition of the oil. to investigate for contaminants, and more.

Checking with your motor oil for expiration, let’s first look at your expiration date. Also, if your motor oil has had a five-year shelf life, then remain cautious for your engine’s sake and go purchase new motor oil.

Now use your dipstick and cloth. Dip your stick into the oil. wipe it on a cloth and look at your motor oil. does it look cloudy? This means that water or too much condensation has gotten into the motor oil solution.

Other signs include whether your oil’s additives have separated. Has your motor oil turned into a solid mixture? Does your motor oil have a sticky density? If any of these signs exist, please dispose of the oil.

Also, check your motor oil’s coloring. Good motor oil features a clear or amber appearance. Any change in its traditional color is an indicator that your motor oil has turned bad or is turning bad. Thus, your motor oil is unstable, and the oil is not safe to use in order to keep your engine running smoothly.

How Does Oil Expire in the Engine of Your Car?

A close-up of the oil being poured from the bottle into the engine.
A close-up of the oil being poured from the bottle into the engine.

Motor oil will turn bad sitting in the engine of your car if you have not moved the car or have not run your car for an extended amount of time. Motor oil base additives that protect and lubricate the engine will fail or degrade, thus becoming less effective in lubricating the engine.

Harmful chemical acids can easily form at the bottom of the sump reservoir, as will water condensation because the exterior temperature changes around your car’s environment

Condensation forms moisture inside the engine and it does not dissolve within engine oil Water is denser than oil. As such, a combination of oil and water will settle down to the bottom of the engine and deposits a thin film onto the engine’s metal components – this is not good!

Normally, when a car’s engine is running, moisture evaporates due to the heat, if a car is left sitting for a long time, moisture will begin to rust the engine’s metal parts.

If oil remains in a car that has been idle too long, sediments will build-up.

If oil remains in a car that has been idle too long, sediments will build-up. Please note that the oil in your engine is a dirty environment. This is because of ash residue, burning oil. and minuscule amounts of metal from inside the engine’s mechanical system.

Letting your car sit without running for an extended period will increase the amount of sediment build-up in your car’s engine. This can potentially create irreversible and expensive engine damage.

If you plan on keeping your car stationary for more than a month, then you should drain the oil completely before you store the vehicle. Draining will prevent oil sediments from building up in your car’s engine, which can be difficult and costly to remove.

The exact amount of time that engine oil, especially synthetic oil, can sit around unused inside an engine will vary. In an environment where it remains idle within a vehicle’s engine system, then yes it will lose most of its lubricating properties.

Additional factors that allow motor oil to expire in the engine of your car involves the exterior temperature, humidity, and the type of oil it is composed of.

Climate also affects how oil expires in the engine of a car. For example, if you’re living in a state like Utah whose has a dry air environment, then the oil inside your car’s engine can sit for a longer time than a state with a high humidity content like Georgia has.

For this reason, because the ambient humidity is low year-round, there is less chance of moisture forming inside the engine system.

There are four basic types of engine oils. They include mineral oils, synthetic, semi-synthetic and premium mineral engine oils. They each have different additives and chemical properties which differ them from each other, depending on your car’s engine system.

If you are using mineral engine oils that are created crude petroleum crude oil. their consistency will break down if affected by heat, water, light, and oxygen. All motor oils should be stored in the right environment and well-sealed.

In summary, synthetic oil can remain in an unused car engine for up to 2 years before it loses its lubricative and protective engine properties. If you live in a dry environment, then these time frames can be extended by an additional year or maybe two.

Expert Tip: Synthetic blend and conventional motor can only remain beneficial to the engine oil for up to 1 or 1.5 years. Mineral oil blends do not have a long life because it is subject to oxidation and creates a chemical breakdown of the oil.

Remember as we have indicated, engine oil doesn’t go bad sitting in the engine. Instead, the additives that protect and lubricate the engine degrade and become no good to any type of engine, thus the oil becomes expired.

Lastly, apart from the moisture contamination, engine oils can also lose their effectiveness while sitting in a car’s engine because of its reaction with oxygen.

The additives inside the oil include detergents, friction modifiers, antioxidants, corrosion inhibitors and viscosity index improvers, all of which are subject to oxidation which makes its chemical makeup turn corrosive or acidic.

2018 Subaru Crostrek 36315 km or 22.5k miles 1st oil change


Changing your motor oil will depend on the age of your car. how you drive your car. road conditions, and the type of motor oil used. Modern car makers suggest changing your motor oil between 5.000 to 7.500 miles.

Does motor oil expire? As we have talked about, motor oil is affected by many factors which determine its expiry timeframe and other factors.

Mainly, motor oil goes bad depending on how you store it. Remember that the best environment to store the oil is a place that is dry. cool, and semi-dark Keeping motor oil in a humid area is the result of contamination.

Remember if there are any signs of oil issues that we have discussed above, have your car checked immediately. If you have any questions, contact us so that we can help you keep your car in excellent running condition.

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About Matthew Webb

Hi, I am Matthew! I am a dedicated car nerd! During the day, I am a journalist, at night I enjoy working on my 2 project cars. I have been a car nerd all my life, and am excited to share my knowledge with you!