Updated at: 30-06-2022 - By: Lucas

Engine oil keeps the engine running smoothly and protects its parts. It also keeps the engine from wearing out too quickly. But because it can catch on fire, you may be wondering if motor oil is flammable and how to store it safely.

Motor oil is not a liquid that can catch fire, but it can be burned. It has a flashpoint of 419 degrees Fahrenheit (215 degrees Celsius), which is higher than the threshold for flammable liquids in the auto industry, which is 199.4 degrees Fahrenheit (93 degrees Celsius).

Materials that burn with air are called combustible, while materials that burn quickly are called flammable. Motor oil can catch fire if the temperature is high enough, so let’s look at this in more detail.

Is Used Motor Oil Flammable?

Is Motor Oil Flammable

If you want a quick answer to the question of whether used motor oil is more flammable, the answer is no.

Oil usually gets softer and less thick when it oxidises, making it easier to mix with gasoline. But even if the oil is very oxidised, it won’t catch fire easily when put near a flame because it has a high flashpoint.

The flashpoint is the temperature at which enough fumes are given off to start a fire. Because it has a high flashpoint, motor oil needs to be very hot to catch on fire.

Motor oil is a mixture of long-chained hydrocarbons, which makes it a heavier liquid. To vaporise, it needs more energy or a higher temperature. It does catch fire, but only at temperatures that are much higher than the flashpoint.

When deciding if a liquid is flammable, the most important factor is whether or not it can produce vapour that can automatically catch fire. Most liquids that can catch fire have short-chained hydrocarbons.

Since the short molecules evaporate quickly, they can catch fire at lower temperatures.

Is Synthetic Oil Flammable?

Because it has hydrocarbons in it, synthetic oil can catch fire. But its flash point is high, which means that it can work at very high temperatures without catching fire or falling apart.

Most of the time, synthetic oil burns slower than regular motor oil because it needs higher temperatures to start.

For most brands, the flashpoint of synthetic oil is about 440 degrees Fahrenheit (227 degrees Celsius). The flashpoint of premium brands is between 450 and 500 degrees Fahrenheit (232 to 260 degrees Celsius).

Compared to other liquids that can catch fire, like gasoline, which has a flashpoint of about 40 degrees Fahrenheit, synthetic oil is pretty easy to light (4.4 degrees Celsius).

Can Motor Oil Spontaneously Combust?

Is Motor Oil Flammable-3

The chance of motor oil catching fire on its own is low. But under the right conditions, motor oil or things that are soaked in oil can catch fire on their own.

When some oils are exposed to air, they oxidise, which is a chemical process that creates heat. This oxidation process is what causes things to burn on their own.

Since motor oil doesn’t oxidise, it can’t catch fire on its own. Without something else to light it, motor oil can’t start a fire on its own.

Can You Burn Motor Oil?

If you want to get rid of old motor oil, you might be wondering if it’s possible to burn it.

Motor oil can be burned, but the smoke it makes has a lot more carbon monoxide than other types of smoke.

This means that it is not only dangerous, but it may also cause cancer. Because of these things, it’s not a good idea to burn motor oil in public.

So how can we safely burn oil?

Even though it’s not safe to burn motor oil in general, there are machines that are made to do just that. These are furnaces that are made to get heat from motor oil, hydraulic oil, fuel oil, and transmission fluid.

If you have a lot of used oil, this can be a great way to heat your home or business while keeping costs down.

How Can You Safely Store Oil?

Motor oil is not flammable, but it is easy to start a fire with it. Most things that can start a fire have flames that are hotter than 400 degrees Fahrenheit (204 degrees Celsius).

This means that if motor oil touches a flame like this, it will get hot enough to catch fire. Because of this, how we store motor oil directly affects our safety.

Some things to keep in mind about safety are:

1. Ensure there’s Sufficient Ventilation

When storing a lot of motor oil, it is very important to keep the concentration of vapours in the storage space low.

The building should have either natural or mechanical ventilation that works. The cost of making sure mechanical systems are safe can be high.

It’s best to use natural air flow, which you can do by opening up two store walls. On one side of the wall, we can put fixed louvres to keep vapour from building up.

2. Spill Containment

Facilities that store liquids that can catch fire should have a sump at the bottom to catch any leaks.

The size of the sump depends on how much oil is in it.

3. Protection from Ignition Sources

To keep people and property safe from fire, motor oil must be kept in a safe place away from sources of ignition. This includes things like open flames, equipment that makes static electricity or sparks, and hot materials.

Whenever you can, use an electric heater instead of a fire. At least 3 metres should be between you and the storage unit.

If you want to store a small amount of oil, put the bottle in a bucket of sand. The sand helps to soak up any spills and stops any fires from starting.

Frequently Asked Questions (FAQs)

What Happens to Used Motor Oil?

When used motor oil is refined, it can be used to make asphalt and heating oil, both of which are made from petroleum. Reusing oil cuts down on waste, which is good for the environment.

Can Motor Oil Combust on Exhaust?

At idle, a hot exhaust manifold can reach temperatures of up to 300 degrees Fahrenheit (149 degrees Celsius). When there is a lot of work to do, the temperature can go above 1400 degrees Celsius (760 degrees Celsius).

Since this is above the flashpoint of motor oil, it can catch fire.


Motor oil is one of the most important fluids for engines. Motor oil does more than just keep things moving. It also neutralises acids. Regular motor oil and synthetic oil can both catch fire, but only at very high temperatures.

We can be sure that if you light a cigarette near motor oil, it won’t go off. But it will still catch fire if it comes in direct contact with a spark or if the temperature goes above 400 degrees Fahrenheit (204 degrees Celsius).

Motor oil can be burned, but it won’t catch fire. We should always be careful to keep ourselves and those around us safe.