If you are like many other car owners, you like to store motor oil at home for topping off or for future oil changes. So when it’s time for either one, chances are you’ll dig out that old bottle of motor oil that has been lying around in the back of your garage. But how do you know if it’s still good to use? And does motor oil expire?
In this article, we’ll answer these questions and discuss the longevity of motor oil. We’ll also give you tips on telling if it’s time to dispose of the oil. Let’s get started!
Does Motor Oil Expire?
Motor oil does expire as engine oil degrades over time, leaving the oil less effective. This natural process is due to the breakdown of the additives that keep the oil fresh and protect your engine, and that is why manufacturers put an expiration date on the oil container.
But determining the quality of the oil is not as simple as just looking at the expiration date labeled on the container. Motor oil can also go bad from sitting too long in a car engine – which is why we frequently change it. But also when it’s stored improperly.
But both conventional and synthetic oil is believed to stay stable under optimal conditions. And in fact, motor oil can last for years without losing its effectiveness.
But there are a number of factors that can affect the longevity of your motor oil, including extreme temperature changes, synthetic additives, and oxidation. And in addition to this, how you store your motor oil also plays an important role that affecting its shelf life.
Fortunately, we have a few tips for you to ensure that the oil stays good for years to come. But first, let’s look at how long motor oil lasts.
How Long Does Motor Oil Last?
The shelf life of motor oil is typically between five and eight years. However, how long motor oil lasts depends on a number of factors, including the type of oil, the conditions it’s stored in, and how it’s used.
For example, conventional motor oil, also called mineral oil or regular oil, is made from refined crude oil and won’t last as long.
Synthetic motor oil, unlike conventional oil, is artificially manufactured and enriched with synthetic additives. These additives offer superior chemical stability and enhance performance in both low and high temperatures. Consequently, synthetic motor oil tends to outlast conventional motor oil.
Having said that, how long the motor oil lasts is highly affected by these three different scenarios.
- If the container is not yet opened
- If the oil has been exposed to air, dirt, and moisture
- If the oil is being used
Let’s take a closer look.
If you have an unopened container of oil (both conventional and synthetic), you can pretty much rest assured that it will last until its expiry date.
Conventional motor oil lasts about five years in unopened containers while synthetic and synthetic blend oils will last about seven to eight years, and you should find the expiry date printed on the oil container.
So it’s a good idea not to open the bottle at all unless you need to use it. But generally, you want to use the oil as soon as possible after purchasing it. Also, remember that the expiry date applies when the oil has been properly stored.
The shelf life of a half-opened motor oil container is a bit more complicated. If you open a bottle of motor oil you’ll expose it to air, dirt, and moisture. In addition to this, opened bottles also make the oil vulnerable to oxidation. And if this happens, it will result in sludge formation and sediment, making it less efficient in the car engine.
So with a half-opened oil container, the expiry date of the motor oil will dramatically be reduced, which means you can no longer expect to go with the date printed on the container.
Instead, for both conventional and synthetic motor oils, it’s best to use the oil within one year of opening, given that the container is sealed tightly and stored in a dry location under normal conditions.
Motor Oil that Is Already in Your Car
The final scenario is motor oil that’s already in your car. But, as long as you drive and change the oil regularly as part of your vehicle’s routine maintenance, you have nothing to worry about.
But when the motor oil is being used, it’s usually the miles that matter and you can’t consider the expiration date on the container as a guideline when you should change the oil in your car.
How Long Does Motor Oil Last in a Car?
Well, it used to be around every 3,000 miles or two to three times a year with conventional oil. But most vehicles today run synthetic and with modern lubricants most vehicles have recommended oil change intervals between 6,000 to 10,000 miles. In some cases, it might even be as long as 16,000 miles with full-synthetic motor oil.
However, the recommended intervals for synthetic oil can vary greatly between manufacturers. And if you’re unsure what the correct oil-change interval is for your car, the best place to find it is in the owner’s manual.
Keep in mind that an exception is if you don’t regularly drive and if the car is standing still for long periods. For example, if you’re going to store your vehicle for more than a month, you should change the oil before storage rather than after.
This is because degraded oil that is stagnant in the engine can lead to acids causing corrosion and sediment formation due to oxidation – similar to the oil stored in half-opened oil containers. Although many think this doesn’t make much difference, it does. In the worst case, it can actually cause permanent damage.
Signs It’s Time to Change Your Motor Oil
- The oil change reminder comes on
- The check engine or oil light comes on
- Your car’s engine is making a knocking noise
- The color of the oil is dark and dirty
- Your car’s performance feels sluggish
Read more: What Happens If You Don’t Change Your Oil?
Can You Use Expired Motor Oil?
If you use old motor oil, chances are the viscosity or thickness of the motor oil is too high or too low and that the motor oil has lost its effectiveness.
If the oil can’t flow freely and reach all components, or if it’s not able to coat the parts of the engine effectively.
It will likely lead to increased wear and tear on your engine, which can shorten its lifespan and even damage your engine beyond repair. So, for this reason, it’s always best to use fresh motor oil when changing your car’s oil.
Read more: Can You Add Oil To A Hot Engine?
3 Ways to Check If Your Motor Oil Has Expired
It’s not always easy to spot when motor oil has gone bad. But with these signs, you’ll have a good idea when it’s no longer good.
1. Check the Expiry Date
As discussed, all motor oils have an expiry date that tells you when the oil starts to degrade and lose its effectiveness. But this doesn’t happen overnight, and it doesn’t necessarily mean the motor oil is bad when the date has passed.
But it generally means that the motor oil is no longer suitable for consumption and that it’s best to dispose of it.
You can usually find the expiry date printed on the container or the bottom of the can. If you cannot find the expiry date on the bottle or container, make sure you use up any unopened motor oil bottles within 2-5 years of the manufacturing date and half-opened oil within a year of opening.
2. Check the Color
Fresh motor oil is usually a light golden or amber color. As it begins to break down and oxidize, it will darken and turn black and muddy.
Most of us regularly look at the dipstick to check the oil level on our vehicles, which is great. But when doing that, many forget or don’t give any thought to the color or appearance as long as the oil level seems okay.
But if the oil on the dipstick is black and muddy, the oil has probably oxidized, which means it’s probably time to change it.
Although, the dark color could also indicate it has been contaminated with moisture, dirt, and wear particles from the engine. But in either case, it’s likely unfit to use.
Motor oil should be clear, translucent, and not appear milky or hazy. If you notice any of these changes to the color or appearance, it signifies that the oil has gone bad and probably has expired.
3. Check the Consistency
Finally, the consistency of the motor oil can also give you some clues about its quality. Motor oil should be smooth and have a clean flow.
But if it’s starting to thicken up or become gooey, it’s a sign that the oil is no good and has probably expired.
So any motor oil with gooey or slime-like consistency is a big warning sign and means you don’t want it in your car because it won’t lubricate and protect the engine as it’s supposed to.
How to Properly Store Motor Oil
If you want your motor oil to last as long as possible, you need to store it properly. Engine oil manufacturers, such as pennzoil, castrol or mobil, all typically recommend you follow these three steps:
1. Store It in the Original Container
The best way to store your motor oil is in its original container. And unless you need to use it, it’s always best to keep it unopened until you have no other option.
But even after you open it, it’s still best to leave it or the rest of the oil in the container it came from. This way you will keep it as clean as possible and prevent it from reacting with any contaminants such as dirt and dust. Don’t forget to make sure the lid is on tight!
2. Store the Container in a Dry Location
Motor oil should always be stored in a dry place and preferably where it is cool and dark, and away from direct sunlight to make it last longer.
Moisture, air, and UV rays can react with the motor oil and cause it to oxidize, leading to acid formation. And storing it in a dry location is even more important if the bottle has been used. And with less oil in the container, there is a higher risk of condensation inside the bottle.
3. Keep It in Consistent Temperatures
Ideally, you should store your motor oil at consistent temperatures for it to last longer, and manufacturers usually recommend motor oil to be stored in temperatures between 40- and 85ºF. And it doesn’t matter if the bottle is open or not.
This is because extreme cold or heat can break down the oil, which affects the viscosity and make it less effective.
But not only that, motor oil is also classified as Class II flammable and has a flash point between 420 and 485ºF. This means that it can catch fire at high temperatures.
So it’s essential you keep the container away from sources of high heat and fire hazards.
Storing and Disposing of Old Motor Oil
Motor oil is classified as hazardous waste, so you can’t just pour it down the drain. The good news is that there are many options for disposing of motor oil, and some of them might even be easy and convenient for you.
The best way is to take it to a recycling center or local waste collection outlet that takes used motor oil.
Another option is to check with your local auto parts store or service station to see if they will take it. Many of these places will have a special container for collecting used motor oil.
Until then, store the old oil in a tightly sealed container and remember to keep the container away from the reach of children and pets. Also, make sure to label it as used or expired motor oil.
Now that you know a little more about the shelf life of motor oil, how to store it and also how to tell if the motor oil is bad, it’s up to you to decide whether or not the oil is still usable or if it’s time to change the oil in your car. And next time someone asks “Does motor oil expire?” you’ll know exactly what to answer.
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