Is Engine/Motor Oil Flammable?

Changing the oil in your engine is a crucial part of vehicle maintenance. It is one of the first things you learn to do - like changing a tire or bleeding the brakes on your motorcycle.

But while these maintenance tasks are rather basic and easy to do, changing the oil in your engine may come with a few extra risky hazards.

If you are about to change the oil in your engine, then you should be educated on the risks these oils can pose - especially when it comes to fire. Here is everything you need to know about engine and motor oil, and what you can do when changing your engine oil to keep yourself safe.

Is EngineMotor Oil Flammable

What Is Engine Oil And Motor Oil?

Engine oil and motor oil are both the exact same products - manufacturers just label them ‘engine’ and ‘motor’ oil interchangeably. For the purpose of this article, we will continue to refer to engine/motor oil as simply engine oil.

Despite the difference in name, they both are made of the same components and are used for the same thing: to lubricate an engine.

Engine oil is an oil made from crude petroleum, designed to lubricate the inner components of an engine. It is also used to protect the components against corrosion and to keep them cool while the engine is in use.

This helps to keep your engine clean and running. The oil is created from two main elements: the base stock, commonly made from either petroleum or synthetic chemicals, and additives that are responsible for protecting the engine parts from wear.

Engine oils are rated by their grade and viscosity (stickiness and thickness). 

Basically, engine oil is a vital part of the engine that keeps it running cleanly. Without it, engines can overheat and corrode. Over time, the oil’s ability to do its job deteriorates and this is when the oil in an engine needs changing. 

Changing your engine oils is not a difficult task, but it does involve draining your engine parts of its oils - at least a gallon of the stuff is sure to come straight out of your engine when you drain it.

With all that exposed liquid and spillages are more than likely, what kind of hazards does engine oil pose - especially when there’s fire involved?

Is Engine Oil Flammable?

For a liquid to be considered flammable, it needs to have a flashpoint of less than 100 degrees Fahrenheit.

A flashpoint is the minimum temperature that a liquid will form a vapor above its surface that is able to be ignited - the lower the flashpoint, the easier it is for the vapor to ignite. A flammable liquid is basically a liquid that reaches this flashpoint at ambient temperatures. 

Engine Oil is not classed as a flammable liquid as it has a flashpoint as low as 350 degrees Fahrenheit - way above the maximum 100 degrees needed to be considered flammable.

This means that engine oil will not produce enough vapor to ignite at room temperature, unlike gasoline which has a flashpoint of -40 degrees Fahrenheit and requires handling with extreme care. 

However, this does not mean that engine oil is incapable of catching fire. 

If the engine oil is heated up to its flashpoint, it will still catch fire. This may occur if your vehicle’s engine has low oil levels or leaks.

The engine oil is used to keep the engine cool when in use but if it is low on oil, the engine’s temperature will increase and so does the likelihood that your engine oil will catch fire.

As for leaked engine oil or engine oil that is stored close to a heat source, if the oil is exposed to heat or flame for long enough to reach its flashpoint of a minimum of 350 degrees Fahrenheit, then the oil will ignite. 

So what does all this mean?

It means that engine oil is unlikely to be the first cause of a fire - unlike gasoline and a flame. Dropping a match in a small puddle of engine oil will not create the same explosive reaction as it would with some other oils, but it still can catch fire.

If you leave the match there long enough to heat the oil, eventually a weak flame will start and if it is left unsupervised, it will grow and grow as the flames heats up the engine oil. 

How To Deal With An Engine Oil Fire

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If engine oil is involved in a fire, it is classed as a Class B fire and will need extra measures to be extinguished. 

A Class B fire occurs in environments involving flammable liquids and oils like paraffin, gasoline, and engine oil. Despite not being classed as a flammable liquid, engine oil fires are grouped into this category because it needs the same measures to be extinguished.

Class B fires cannot be extinguished using water - in fact, trying to douse a Class B fire with water in an attempt to extinguish it will only make the fire worse. Flames will grow taller and the oil will splash, meaning that the fire can spread easier and grow more intense.

So if you are faced with an engine oil fire, do not try to extinguish it yourself using water. You will only make things worse. 

To extinguish an engine oil fire, you will need to use a Class B fire extinguisher - usually a carbon dioxide fire extinguisher. To extinguish a Class B fire like engine oil fires, you need to smother the fire and completely cut off its oxygen supply.

Oxygen is what helps feed a fire along with fuel and heat, so cutting off a fire’s oxygen supply will cause it to die. As water cannot be used, the next best thing is carbon dioxide.

A carbon dioxide fire extinguisher will dispel carbon dioxide, smothering the fire and extinguishing the flames without the risk of spreading the fire. 

If you own a garage or have a space where you often perform your car maintenance, then it is advised that you purchase a Class B fire extinguisher so you can use it against fires involving flammable liquids like gasoline or engine oil. 

If you do not have a Class B fire extinguisher at hand, then you will have to evacuate the area and call 911. Your local fire department is made up of expert firefighters, who will have the right tools and equipment to tackle the fire appropriately.

Make sure to tell the dispatcher what has happened and where the fire is, so the fire department can equip themselves appropriately. 

In most cases, this is what you should do in any fire-related event. Trying to extinguish a fire yourself can put you at risk, especially if you make easy mistakes like trying to extinguish a Class B fire with water.

Unless you are expected to extinguish the fire yourself, then it is strongly advised you call your local fire department so they can extinguish the fire and you do not put yourself in harm’s way. 

How To Store Engine Oil

So really, engine oil poses very little threat as a fire hazard. It is difficult to catch on fire, but not impossible, which is why it is vitally important to handle engine oil with care and caution, and store it appropriately. 

Properly storing your engine oil will greatly reduce the odds of it being involved in a fire, and will save you a lot of hassle and money. Engine oil should be stored in clean, plastic containers and appropriately labelled.

Also, make sure that you correctly label your engine oil as ‘used’ or ‘new’ so when it comes to changing the oils in your engine, you know which is which and you do not accidentally pour the old oil back into the engine. 

The container should remain sealed and be stored in a dry environment, away from sources of high heat and fire. If the engine oil is exposed to prolonged periods of high temperature, then the oil will heat up until it reaches its flashpoint and catches fire.

Avoid this by keeping the oil away from such fire hazards - this is the crucial part of storing engine oil effectively.

If you spill any engine oil or a container containing engine oil leaks, you will have to clean it in order to avoid it from being exposed to any flames or heat.

Spilling oil when changing your engine’s oil is a common occurrence, so don’t panic if this does happen as it is very easy to clean up. You can soak up the oil using kitty litter or sawdust, then sweep it all up and dispose of it.

Then, clean up any stains by using dish soap and water. You can purchase specific solutions designed to clean up engine oil spills, but plain old soapy water will do just fine. Simply scrub the stain with a brush until the stain disappears and then rinse the spot with a hose.

Engine oil is a pollutant, and so to dispose of it properly, do not spill or tip it anywhere outside. Take the used engine oil to the appropriate facilities and service stations near you. They will take your used engine oil off your hands - including that kitty litter you used to soak up any puddles.

There are many reasons for a leaking engine, but if you notice your engine is leaking oil, then you need to take it to a mechanic immediately so they can inspect your vehicle and fix the leak.

Driving with a leaky engine is extremely dangerous as you pose a threat to yourself and to other drivers as your vehicle can catch fire or your engine may stop while you are driving. Contact your mechanic and they will help you work out what to do from there. 

What About Synthetic Oil?

Synthetic oil does not differ much from regular engine oil in terms of flammability. It generally has a higher flashpoint, requiring hotter temperatures for it to produce enough vapor to ignite.

This makes it a little bit safer to use than regular engine oil but regarding the fact that both need to be heated to extreme heats in order for the oil to catch fire, it does not make that much of a difference.

If your synthetic engine oil does catch fire, however, then it should be extinguished the same way as regular engine oil - using a Class B fire extinguisher. 


So is engine oil flammable?

It is not classified as a flammable liquid, but it still can ignite when heated to its flashpoint of at least 350 degrees Fahrenheit. Some engine oils may have a higher flashpoint, but they all should not reach these kinds of temperatures unless they are stored incorrectly.

Just remember to store your engine oils correctly and to wash away any spills, then you won’t have to worry about a fire breaking out in your garage due to engine oils.