Is Engine Or Motor Oil Flammable?

Can motor oil catch on fire? If so, at what temperature? Here's a super simple guide that explains the flammability of engine or motor oil.

Answer:

Engine oil (motor oil) will catch fire if exposed to high temperatures.

This is typically between 300°F (150°C) to 495°F (258°C).

Are you worried that engine/motor oil is flammable?

The short answer is, technically, no. Motor oil is combustible. This classification means it’s slightly less likely to catch fire than something “flammable.”

That said, engine oil will still catch fire if exposed to high enough temperatures. You should always store it well away from anywhere hot or anything likely to ignite.

In this easy manual, I will guide you through the dangers of fire from motor oil.

Table of ContentsShow

What Is The Flash Point Of Motor Oil?

Fuel Flashpoint

The flash point of a liquid is the lowest temperature at which it gives off vapors that could ignite.

The flash point of engine oil can be anywhere between 300 and 495 degrees Fahrenheit.

The approved maximum limit to be considered flammable is 199.4 degrees Fahrenheit. It’s clear that motor oil surpasses this.

Compare this to gasoline. Gasoline is much more flammable and has a flash point of about 40 degrees Fahrenheit.

Motor oil, distilled from raw crude oil, has a high flash point. This is due to its long hydrocarbon chains.

You could think of it as “heavier” than most flammable liquids. Longer, heavier chains require more energy (heat) to vaporize.

Because of this, it’s much less likely to ignite (except in extreme circumstances).

Does Car Oil Burn?

Burning car

Usually, motor oil doesn’t get too hot, about 300 degrees at most. But if something goes wrong with your engine, like the piston rings break or the head gasket blows, the oil could end up in the combustion chamber.

It will ignite and produce a cloudy smoke that has a blue/gray hue.

This is an immediate cause for concern. You should drive straight to your local mechanic.

In short, yes. The oil in your engine will burn if exposed to high enough temperatures.

Is Used Motor Oil More Flammable?

Hazard Warning Sign Flammable

Preowned motor oil isn’t any more likely to ignite than fresh oil.

Over time, used motor oil does lose its viscosity. It’s more likely to mix with gasoline vapors.

Still, the liquid has a very high flash point, meaning it will only catch fire under extreme heat.

Again, it’s technically proper to refer to engine oil as “combustible” rather than “flammable.”

Is Synthetic Oil Flammable?

Synthetic Motor Oil

Synthetic oil (used in most cars these days) is marginally less likely to ignite than regular oil, in general.

It usually requires higher temperatures for combustion. As such, the flash point and fire point are higher.

All types of engine oil have a very high flash point. You shouldn’t worry about spontaneous combustion, although do maintain some common sense.

For example, storing motor oil next to a hot exhaust or wood stove wouldn’t be sensible.

Can You Burn Motor Oil?

motor oil

It’ll be very difficult to burn motor oil by itself. It’s more likely to burn if you soak another material in the oil (for example, a cloth). It’ll still be challenging to get it hot enough to ignite.

Although it’s possible, you shouldn’t ever burn motor oil. It’s polluting and damaging to your health. The smoke also contains a high carbon monoxide content.

Instead of burning oil, dispose of it according to local governmental rules. You usually need to take all waste oil to an oil disposal plant.

How Should You Store Motor Oil?

Car Engine Oil

Follow a few basic principles to store your motor oil securely.

  1. Keep it well away from sources of heat or ignition (such as those mentioned above).
  2. Ensure the area is well-ventilated to remove vapors.
  3. Store it on a sump. Most official oil storage locations (like an auto shop) will store oil on a grate over a sump. If any of it leaks or spills, it’s safe.
  4. Clean up spillages immediately. Use granules or sawdust for this.

Is Motor Oil Flammable? Conclusion

While motor oil might not be flammable in technical terms, it can still catch fire. You should still store it carefully and not hold more than you need.

If you notice your car burning oil – which isn’t that uncommon, particularly on older cars – head straight to a mechanic. You might have a serious problem. The quicker it’s identified and remedied, the cheaper it’ll be.

Finally, don’t incinerate motor oil. It’s hazardous and poisonous. Always dispose of it in the recommended, safe manner by heading to a recycling plant.

You Might Love These

Are Electric Cars Safe
Are Electric Cars Safe?
Benjamin Kitchen

Ben is an IMI-qualified light vehicle technician from England with experience in a fast-fit garage. He aims to help drivers worldwide with common automotive problems. You’ll often find him working with his 1.2 Vauxhall Corsa. It may have a tiny engine, but in eight years it's never once let him down!