Are you worried that the engine oil in your hot engine can cause a fire?
Perhaps yes.
But is engine oil even flammable to begin with?
No.
Engine oil isn’t flammable.
Yes, it can catch fire if you really want it to burn, but so does the shirt you’re wearing.
Read on to learn why engine oil isn’t flammable and what you can do if it starts burning.
Here’s what we’ll cover:
Why Engine Oil Isn’t Flammable?
That requires us to understand the flash point.
Flash point is the lowest temperature at which a material releases enough vapors that can burn. This temperature decides the flammability of a substance.
According to the Occupational Safety and Health Organization (OSHA), only substances with a flash point below 199.4 degrees Fahrenheit (or 93 degrees Celsius) are considered flammable.
Engine oils’ flash point is around 300-495 degrees Fahrenheit (or 150-260 degrees Celsius). In other words, engine oils aren’t flammable liquids.
In contrast, gasoline’s flash point is -40 degrees Fahrenheit. That’s why gasoline burns so quickly.
Can Engine Oils Burn?
Yeah, engine oils can burn.
Similar to a paper or cloth, if you exceed the flash point of an engine oil and ignite it, it can burn.
Here’re different scenarios when that could happen.
Overheated Engine
Temperatures in an overheating engine can exceed the flash point of engine oils. In such cases, if the engine oil finds its way past the piston ring, it’ll burn and can cause serious fire hazards.
Oil Leaks on Exhaust Manifolds
Exhaust manifolds can have a temperature of over 1000 degrees Fahrenheit. Engine oil dripping on the exhaust manifold will vapourize instantly.
But if enough oil is present, it can cause a fire. Similarly, the evaporated oil can come in contact with a spark and cause a fire.
External Spark
The temperature of a spark is well over 1500 degrees Fahrenheit. If the engine oils come in contact with a continuous spark, they can heat up to above their flash points and cause a fire.
Engine Oils and Their Flash Points
We mentioned above that the flash points of engine oils range between 300 and 495 degrees Fahrenheit. That doesn’t mean engine oil is a moody substance that burns whenever it wants.
Instead, different engine oils can have different flash points. So we mentioned an overall range that covers all types of engine oils.
Let’s explore the flash points of different engine oils.
Conventional Engine Oil
Conventional engine oil refers to engine oil refined from crude oil. They have flash points ranging from 300-400 degrees Fahrenheit.
Synthetic Engine Oil
Synthetic engine oils are artificially manufactured oils. These oils can have flash points ranging from 440-500 degrees Fahrenheit.
Synthetic Blend Engine Oil
Synthetic blend oil is a mix of synthetic base and conventional engine oils. These oils offer higher quality due to the synthetic base. These engine oils can have flash points ranging from 360-450 degrees Fahrenheit.
High-Mileage Engine Oil
High-mileage engine oils are designed to get more miles off your car. These oils are formulated with anti-wear agents to help slow down your engine’s wear and tear. These oils are recommended for vehicles with 75,000 miles or above.
High mileage engine oils can have flash points ranging from 420-500 degrees Fahrenheit
How To Kill Engine Oil Fire?
If engine oil comes in contact with a spark at room temperature, it won’t burn. But if the heat source (spark) is present for long enough, it can start a fire.
If that happens, you need to extinguish that fire. For that, remember that an engine oil fire is classified as a Class B fire in international standards.
Here’s how to extinguish a Class B fire.
- Use Class B Fire Extinguisher (CO2): Use a carbon dioxide extinguisher to extinguish a Class B fire. It can smother and extinguish the flame without risking the spread of fire.
- Avoid throwing water on the fire: Trying to extinguish a class B fire with water can worsen the fire. Throwing water on burning oil makes it splash and causes flames to grow taller. It means the fire spreads and grows more intense.
- Cut off Oxygen supply: Oxygen feeds the combustion process. In any fire, an effort should be made to cut off the oxygen supply. Using a fire extinguishing blanket can help to cut off the oxygen supply.
- Call the local fire department: Your local fire department can handle all kinds of fires. Expert firefighters have designated tools and equipment to tackle fire properly.
Final Thoughts: Is Engine Oil Flammable — What You Need To Know
Engine oil isn’t a flammable liquid. But it can catch fire if heated up to its flash point.
If an engine oil fire starts, use Class B fire extinguishers to put it out.
Have you ever encountered an engine oil fire? Share your experiences with the other readers and us via comments.
For more information on engine oils, check out our blog.
