Does Motor Oil Freeze?

by Synthetic Oil | Last Updated: June 16, 2022

When dealing with freezing temperatures, you just can’t help but wonder, “Does motor oil freeze?” Amid the chilly cold starts, slick precipitation, and frozen windshield wiper fluid, your car takes a beating. It is no secret that cold temperatures can damage your engine, but do you also have to worry about the oil, too? Today, that is exactly what you’re going to learn.

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Does Motor Oil Freeze?

First and foremost: No, motor oil does not freeze, because it is petroleum-based. Some people confuse the fact that motor oil becomes more solid when it is cold as freezing. However, without the presence of frost crystals, your motor oil is not, by definition, frozen. Therefore, you do not have to worry about your motor oil getting frosty or forming crystals, even on the coldest of days.

What Happens to Motor Oil in the Cold?

However, just because motor oil does not freeze in cold temperatures does not mean it is unaffected. Yes, motor oils stay viscous, and they do not crystallize. That said, the viscosity of engine oil tends to increase in the cold, but it still lubricates your engine. You will need to start your car up and let it run for a little while to prevent damages from cold starts from accruing.

If you do not wait for cold motor oil to warm up, you run this risk of problems. First, cold motor oil takes a long to flow through the engine and coat everything in lubrication. Taking off before the oil has a chance to flow freely could result in increased pressure within the motor, as well as a weakened battery.

Repairing any damages caused during cold starts will be expensive. For the sake of your vehicle, give it plenty of time to warm up during the winter!

Here is a video of “frozen oil” inside a vehicle’s engine:

What Temperature Does Motor Oil Freeze?

You may have heard or seen something called a pour point. The pour point, which is the opposite of the flashpoint, is the lowest possible temperature for oil to pour under normal conditions. What do normal conditions mean? Unchanged viscosity and fluidity. At around 0°F (-18°C), the viscosity of motor oil begins to change, and it may be resistant to flow. So while motor oil does not freeze, its consistency of it does change.

How the cold affects motor oil also depends on the type:

Conventional Oil

Did you know that conventional oil is a little waxy? In the winter, that waxy component is what makes conventional oil flow less freely. At around 15°F, the wax in conventional oil will begin to separate from the oil. You will notice that conventional oil is far more difficult to handle during this time, especially if you attempt an oil change! In fact, it may become so thick that, instead of protecting your engine, it congests it. This begins to happen at around -4°F (-20°C), which is when the minerals in conventional oil start to coagulate.

Synthetic Oil

While synthetic oils do not have the same composition as conventional oil, they still have the same issues in cold temperatures. Synthetic oils generally have a high viscosity index, so they can function in extreme temperatures well. Even below -4°F (-20°C), synthetic oils flow as freely as usual. The standard pour point is around -58°F (-50°C), which is not something you see often.

As long as you have synthetic oil in your car’s engine, you won’t have to worry about it congealing. Synthetic oil does need to warm like conventional oil before use, but it is not as likely to solidify.

How Long Does It Take For Motor Oil to Freeze?

Even in sub-zero temperatures, motor oil will not freeze. However, it does thicken up and becomes more dense—conventional oil more than synthetic. Trying to start an engine when the oil is like molasses is challenging. The thickened motor oil is not going to behave as you want after sitting all night in the cold.

So, even if you let an engine sit overnight or for several nights in freezing temperatures, the motor oil will be fine. It will be slightly thicker than normal and may not function properly without warming up, but it will not freeze.

Can Motor Oil Be Stored Outdoors in the Winter?

Most manufacturers estimate the shelf life of unopened bottles of motor oil to be between 2 and 5 years. However, that is when placed in the optimum conditions. It is never recommended to keep your bottles of motor oil outside during the coldest part of the year. Freezing temperatures may not cause motor oil to freeze, but it does ruin the fluid. Both motor oil and gasoline should be stored in a stable, climate-controlled environment. If oil or gasoline are exposed to extreme temperatures, the chemical composition gets scrambled, and that could reduce the overall performance of the oil.

If you live somewhere that is vulnerable to overnight freezing or temperature fluctuations, do not store motor oil in the trunk of your car. Without insulation, even the garage may not be safe.

Is It Safe For Motor Oil to Freeze?

While motor oil doesn’t freeze, there is still a chance the chemical composition gets murky if you leave it exposed to the elements. Frigid temperatures will cause the oil to deteriorate, making it less effective at its main function: reducing friction in the moving parts of the engine. In short, cold motor oil is ineffective.

Furthermore, motor oil that is left out will not crystallize, but it does get thicker. Since the consistency changes and balls up, becoming far more solid, you may be unable to pour motor oil when it is freezing outside. Remember, at around -20°F, the viscosity of motor oil begins to change, but even at 0°F, there are still noticeable differences in the flow of the oil.

You want your engine oil to run as smoothly as possible to prevent motor damage.

How To Safely Warm Up a Car in the Winter

Briefly, let us describe how to avoid the risks of cold motor oil. Knowing a safe way to warm up the car engine in the morning or when you want to check the oil is smart. Here are some steps to consider when starting your vehicle during freezing temperatures:

• Turn off everything. Since the battery and engine are both going to be sluggish, you want to give your car a fighting chance. Make sure the electronics are turned off. Also, have the defroster, headlights, and wipers switched off.
• Turn on the vehicle. Let the engine crank for about 10 seconds, if it is struggling to turn over. Do not let it go longer than that. Let it rest in between attempts.
• If the engine is close to starting but sounds sluggish, give it another break before trying one more time.
• If the car does not start, remove the battery and warm it up inside. Optionally, you can jump the battery. In some places, investing in a block or battery heater is a good idea, as this can save you some time and effort in the morning.

You should also invest in the right viscosity grade of motor oil. Check your owner’s manual for more information. Manufacturers like Chevrolet or Toyota always have information about the recommended motor oil for the model you drive.

Once you get your car started, let it sit for a little while with everything still off. You may be tempted to switch on the defroster or heater, but it is best to wait a few minutes.

What Is The Best Motor Oil For Winter?

During cold months, you may desire to switch to winter-grade motor oil, which is lighter and thinner than more viscous fluids. Even in cold temperatures, winter-grade oil will flow freely through the engine. How do you know which oil is winter-grade, you ask? Check out the bottle.

When a motor oil has been rated for winter use, there is going to be a W in the name. W means—you guessed it—winter. Typically, the lower the number in front of the W, the better it functions in colder weather. So, when you look at 10w30 vs 5w30, you can tell that the 5w30 is the better choice since it has less viscosity.

Another motor oil that has been specially formulated for the coldest months is 0W. For those locations that struggle from below freezing temperatures and loads of snow, a 0W motor oil, such as 0w30, may be best.

Final Thoughts

A lot of people ask, “Does motor oil freeze?” What they should be asked is what happens to the engine when the motor oil does not have a chance to warm up. No, motor oil does not freeze, but it does get cold and thick and cannot perform its job properly. If you want to protect your vehicle from damage, ensure the oil has enough time to warm up and become more fluid since that is how it protects your engine from damage.