Is Motor Oil Flammable? Igniting the Debate

Motor oil is a common substance that many people depend on to keep their vehicles running smoothly.

It plays a crucial role in lubricating the engine and reducing friction, ensuring optimal performance and longevity. But have you ever wondered about its flammability?

In this blog, we will delve into the topic of motor oil and explore various aspects related to its properties, including its potential flammability.

So, if you’re curious to learn more about this essential automotive fluid, keep reading!

Is Motor Oil Flammable

Is Motor Oil Flammable

Motor oil is considered combustible, but its flammability is relatively low compared to other fuels like gasoline or diesel. While motor oil can burn and produce flames under certain conditions, it has a higher flash point and autoignition temperature, making it less prone to ignite quickly.

The flash point is the lowest temperature at which a substance emits enough vapors to form an ignitable mixture with air. For motor oil, the flash point typically falls between 200 to 250 degrees Celsius (392 to 482 degrees Fahrenheit). This means it needs to be heated to relatively high temperatures before releasing enough vapors to ignite.

The autoignition temperature is the temperature at which a substance spontaneously ignites without needing an external ignition source. For motor oil, the autoignition temperature is even higher, usually above 300 degrees Celsius (572 degrees Fahrenheit).

Is Synthetic Motor Oil Flammable?

Yes, synthetic motor oil is flammable. Like conventional motor oil, synthetic motor oil is a petroleum-based product, and as such, it can burn and support combustion under certain conditions.

However, Synthetic motor oil is engineered to have more consistent properties and higher performance than conventional oils.

The flammability of synthetic motor oil is similar to that of conventional motor oil, and it is essential to handle both types of motor oils carefully to prevent the risk of fire.

As with any flammable liquid, it is crucial to keep synthetic motor oil away from open flames, sparks, and high-temperature sources.

Will Oil Spilled On Engine Catch Fire?

The short answer is yes; oil spilled on an engine can catch fire. However, several factors come into play, and understanding them can help prevent such a dangerous situation.

Firstly, it’s essential to know that oil itself is not flammable. It is the vapors that can ignite and lead to a fire. When oil is spilled onto a hot engine, it can quickly reach its flashpoint, the minimum temperature at which it can ignite.

Another critical factor is the presence of an ignition source. This can be anything from a spark caused by an electrical short circuit, a hot exhaust manifold, or even a lit cigarette.

The fire risk increases significantly if the oil spill is near any of these potential ignition sources.

The engine’s operating temperature also plays a crucial role. A hot machine can heat the spilled oil, increasing the chances of ignition.

Additionally, the heat generated by the engine can cause the lubricant to spread and reach other flammable materials under the hood.

Is Burning Used Motor Oil Toxic?

When motor oil is burned, it releases harmful pollutants into the air. These pollutants include carbon monoxide, nitrogen oxides, sulfur dioxide, and particulate matter. When inhaled, these substances contribute to air pollution and can have serious health effects.

Breathing in these pollutants can irritate the respiratory system, cause lung damage, and even lead to respiratory diseases.

In addition to the health risks, burning motor oil contributes to environmental pollution.

Releasing pollutants into the air can lead to smog formation and contribute to the greenhouse effect, exacerbating climate change.

Dosing particulate matter onto land and water can harm ecosystems and contaminate water sources.

Furthermore, burning motor oil can release heavy metals, such as lead and cadmium, into the environment.

These toxic metals can accumulate in soil and water, threatening plants, animals, and humans. They can enter the food chain and have long-lasting effects on the ecosystem.

Is Motor Oil More Flammable Than Gasoline?

No, motor oil is generally not more flammable than gasoline. Gasoline is a highly flammable liquid fuel composed primarily of hydrocarbons, and it has a lower flash point and autoignition temperature than motor oil.

The flash point of gasoline is typically around -40 to -45 degrees Celsius (-40 to -49 degrees Fahrenheit), while the autoignition temperature is approximately 246 to 280 degrees Celsius (475 to 536 degrees Fahrenheit).

On the other hand, as mentioned earlier, motor oil, whether conventional or synthetic, has a higher flash point, usually falling in the range of 200 to 250 degrees Celsius (392 to 482 degrees Fahrenheit), and an autoignition temperature above 300 degrees Celsius (572 degrees Fahrenheit).

How Hot Does Motor Oil Burn

The temperature at which motor oil burns can vary depending on several factors, including the specific type of motor oil, its composition, and the conditions under which it is exposed to heat or an ignition source.

However, motor oil typically begins to emit vapors that can burn above its flash point, the lowest temperature at which it releases enough vapors to form an ignitable mixture with air.

For most motor oils, both conventional and synthetic, the flash point typically falls in the range of 200 to 250 degrees Celsius (392 to 482 degrees Fahrenheit). At or above this temperature, the oil starts to release flammable vapors.

Storing Motor Oil In A Flammable Cabinet

Motor oil does not necessarily need to be stored in a flammable cabinet under normal circumstances. Unlike highly flammable substances such as gasoline, motor oil has a higher flash point and autoignition temperature, making it less prone to ignite quickly.

However, some precautions should still be taken when storing motor oil to ensure safety.

Here are some general guidelines for storing motor oil:

Keep away from ignition sources: Store motor oil away from open flames, spark-producing equipment, and hot surfaces.

Use appropriate containers: Use sealed containers designed for storing motor oil to reduce the risk of spillage and potential fire hazards.

Avoid extreme temperatures: Store motor oil in a cool, dry place and avoid exposure to direct sunlight or extreme temperatures.

Secure storage: Ensure the storage area is well-ventilated, and the containers are secure to prevent accidental spills.


Motor oil is not highly flammable; its flammability is relatively low compared to highly volatile fuels like gasoline.

Conventional and synthetic motor oils can burn and support combustion, but they have higher flash points and autoignition temperatures, making them less prone to ignite quickly.

While motor oil should be handled carefully and stored away from open flames and ignition sources, it does not require flammable cabinets for typical household or small-scale storage.

Nonetheless, proper handling and disposal of motor oil remain essential to ensure safety and prevent environmental hazards.