Is Engine Oil Flammable or Combustible?

Is car engine oil flammable? The answer to this question is no. Even though it might seem flammable and comes from crude oil, it does not mean it is. However, engine oil is combustible and has a smoke point where it begins to burn.

This article will ensure you understand is engine oil flammable or combustible? We also state the flashing point of engine oil and what oil is not flammable and answer other related questions.  

is car engine oil flammable

Is Engine Oil Flammable or Combustible?

The engine oil is not flammable;instead, it is combustible. Many believe that because it is obtained from crude oil, it increases the motor oil flammability chances, just like other products obtained from crude oil.

People do not know that when a flammable liquid burns, it is not the liquid that burns but the vapor released by the liquid. It is what goes on with gasoline and other flammable petroleum products.

These flammable liquids have smaller molecules with a much weaker intermolecular force of attraction. The molecules are broken apart with little heat, letting the vapor loose.

On the other hand, engine oil has much more heavy molecules. It comprises heavier hydrocarbons with about 18-34 carbon atoms in a molecule. It gives for a much stronger bond between molecules when compared with flammable liquid.  

Engine oil is classed under the C2 combustible substance, which requires a temperature greater than 200 °C to release flammable vapor to burn. But oil expands when get heated.

Flash Point of Engine/Motor Oil

Flashpoint is a critical consideration regarding the fluid used by your engine. It determines how flammable or combustible they are. It is the temperature that an organic compound has to be exposed to before it releases enough vapor for it to ignite.

Regarding engine oil, the flash point is between 200 °C and 280 °C, making it non-flammable but rather combustible. You will understand the reason for this once you know the classes of flammable and combustible fluids.

Flammable liquids are classified into three major classes, which are as follows.

1. Class IA

This class of flammable liquid has a flashpoint of less than 22.8°C and a boiling point of less than 37.8°C.

2. Class IB

The flammable liquid under this class has a flashpoint of less than 22.8°C and a boiling point greater than or equal to 37.8°C.

3. Class IC

This flammable liquid under this category has a flashpoint greater than or equal to 33.8°C but less than 37.8°C.

We need to look at the classes of combustible liquids to understand which category motor oil flashpoint falls on. They include the following.

1. Class II

This combustible liquid class has a flashpoint greater than or equal to 37.8°C but less than 60°C.

2. Class IIIA

This combustible liquid class has a flashpoint greater than or equal to 60°C but less than 93 °C.

3. Class IIIB

The combustible liquid in this class has a flashpoint greater than or equal to 93°C.

When you look at the flammable and combustible liquid classes, you will see that engine oil falls in the Class IIIB of the ignitable liquid. It is because it has a flash point between 200 °C and 280 °C.

Engine oil is not a flammable liquid but a combustible liquid. It will not burn at normal working temperature and might require much more heat to burn. It is why it also serves as a means of cooling the engine. 

What Oil Is Not Flammable?

Generally, motor oil and other types of consumable oil are considered non-flammable. It is why oil exploded under the hood is an infrequent occasion. However, this occurrence is not impossible because they are combustible.  

In addition, rather than having flammable engine oil that will burn under normal working temperature, you have combustible engine oil. It means it requires more heat to burn.

When people ask the question, will motor oil burn? The answer is yes. Just because the oil is not flammable does not mean it cannot burn. 

When the oil reaches above 200°C before it can begin to burn, at this point, the oil will have reached its flashing point and experience a form of ignition which will then result in it cooking up and smoke through oil cap. After staying at this temperature for a while, it turns to soot.

Some oils are considered flammable; however, they are unsafe to use with your vehicle. 

Can Spilled Oil on Engine Catch Fire?

Many car owners have been asking a popular question: Canmotor oil catch on fire? The answer to that question is yes. When you have spilled oil on engine, there is a possibility that it could lead to a fire.

The flash point of engine oil is pretty high, which makes it a nonflammable liquid; however, it is combustible. Oil leaks in the engine will result in a tremendous increase in the engine’s temperature.

The increase in the temperature due to these leaks and low oil in the engine could cause the oil to reach the combustion point. It increases the chances of the engine burning.

Also, if you spilled a little oil on engine during refilling or oil change, clean it properly before using your vehicle.

How To Store Engine Oil?

When storing engine oil, you should note that heat affects the quality of the engine oil. Storing it in a place that is too hot for the engine oil will affect its viscosity.

Many manufacturers advise that oil is stored between 4 °C and 27 °C. It is also essential that the container remains sealed when not in use. It would help if you broke the seal only when ready to use the oil.


Engine oil is a crucial liquid used in vehicles and reacts differently to the temperature it is exposed to. It is why you must pay attention to your engine’s temperature and the oil’s condition. When the oil is too hot, something is wrong with the engine, and more issues might arise.

Akindayini Temiloluwa

I am Akindayini Temiloluwa, an automotive expert writer and car enthusiast. I have over three years of experience in the automotive writing niche and have completed over 300 pieces of content from 50 projects. I have vast knowledge and skill in vehicle repairing, all mechanical work, car upgrades and maintenance. My goal as an automotive content writer is to simplify the most challenging concepts for my readers, help them self-diagnose what may be wrong with their vehicles and offer real value for their time.

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