Is Brake Fluid Flammable? (Why You Should Be Careful With Them)

Is brake fluid flammable? If you look at it, there are a lot of hazardous and highly flammable fluids that are crammed into the tiny space in the engine compartment.

The engine operates at an extremely high temperature, which means the components surrounding it need to be designed with the highest tolerances to ensure that the engine oil, fuel, and other fluids from being in contact.

As a result, knowing the types of fluids that are flammable and which ones aren’t essential.

This article will go over everything you need to know about brake fluids and answer the question, is brake fluid flammable.

Let’s begin

The properties and components of brake fluid need to be understood to understand why it is flammable.

Some brake fluids are made of Ethyl-glycol, and this chemical compound is flammable and burns. Manufacturers of silicone-based brake fluid have argued that the product is not flammable, but a close investigation suggests otherwise. Silicone-based brake fluid is also combustible.

As stated earlier, gasoline is more flammable, volatile, and explosive than brake fluids.

In addition, these brake fluids burn just like vegetable oil with a bit of flame.

Some brake fluids are mineral oil-based; they are also flammable and burn like candle wax.

The question remains, can brake fluid be a cause of fire outbreaks? Brake fluid has low ignition strength, the leading cause of a fire.

To verify and understand the flammability of brake fluid, we will use the flashpoint experiment. This is a situation where a flammable substance transforms into a gaseous state and burns.

Depending on the type of brake fluid flashpoint, it can be as high as 210-375°F or 98.8-190°C.

Brake fluid does not ignite at an average temperature. This is because its ignition capacity is low and can only be achieved at high temperatures, the temperature of 540-675°F or 282-357°C

When an accident occurs, the brake fluid can be burning at the exhaust manifold; it can also result from firing, moving to other parts of the car, and creating a general fire outbreak.

Therefore, brake fluid should be handled carefully, particularly around the fire.

Brake fluid is also very corrosive; if given the proper condition, it can spread to other parts of the vehicle, eating up the metals. Therefore, brake fluid is also very toxic and should not be kept carelessly.

Car paints will get wiped off if hydraulic fluid comes close to it; this is also applicable to fluids with glycol as one of its constituents.

You may be wondering about the DOT 4 brake fluid; well, DOT 4 is a polyglycerol-ether-based hydraulic fluid. It burns at high temperatures, and it has a low degree of flashpoint, which is around 210-357°F

The DOT 4 is more flammable compared to silicon-based brake fluid. However, at a very high temperature, around 540-676°F, it may self-ignite.

DOT3 brake fluid is a glycol-based cold liquid; it is flammable and has less ignite temperature than most brake fluid types. It has a boiling point of 250°C with a flammable rating of 1.

Also Read: Brake Light Blinking (Causes & How To Fix)

What Is the Brake Fluid?

Is Brake Fluid Flammable

A force needs to be applied to the car brake before it will work; this force is mostly the foot force. However, a special fluid is added to the brake to increase this foot force or act as a pressure on the car brake.

This fluid is known as the brake fluid. This fluid works together with the foot force to help the car stop when necessary.

The brake fluid is also known as hydraulic fluid. A vehicle without brake fluid is difficult to stop and dangerous to drive. Brake fluids are used in all cars, motorcycles, and even bicycles.

Before handling bake fluid or fixing brake fluid-related issues, make sure you know what you want to do; otherwise, you will mess things up and create more problems.

Types of Brake Fluid?

There are typically three different types of brake fluid you can find at the market. They are known in the form of the model, which are DOT3, DOT4, and DOT5. 

DOT3 and DOT4 are made up of glycol fluid, while DOT5 is a silicon base fluid.

One important thing to understand about these types of brake fluid is that DOT5 can not absorb water while DOT3 and DOT4 can.

The boiling point of these fluids is also one crucial aspect of them. For hydraulic systems, the compressed fluid is needed for force to be disseminated.

Gases are compressed while the liquid is condensed. Brakes will stop functioning, or their functionality will drop when the fluid becomes gaseous or boils.

Also Read: 9 Bad Brake Booster Symptoms (& Replacement Cost)

How Can Brake Fluid Catch on Fire?

We have established that brake fluid is not as flammable as gasoline. Brake fluid is housed in a well-sealed brake system; it is insulated from outside heat.

The friction between the brake disc and pad at the brake calipers is the only area where brake fluid absorbs heat.

High temperature is the only reason brake fluid will catch fire, and this high temperature is achieved when you expose the brake to too much heat.

And this doesn’t always happen; it is a rare occurrence only when something else close to the brake fluid within the engine gets burning and releases intense heat.

More often than not, this heat will only cause leakage of the brake fluid than it would cause a fire.

Why Is Brake Fluid Flammable?

The flammability of brake fluid is different for different brake fluids types; DOT3, DOT4, & DOT5 are the other brake fluid models common in the market.

DOT5 is silicon-based, while DOT3 and DOT4 are glycol-based. The silicon base is flammable but not like the glycol base, which can quickly catch fire.

Any flammable substance is generally dangerous; However, brake fluid has low ignition power and can not readily catch fire.

Brake fluid can be quite hazardous in accident situations because it will burn and spread to other parts. It is also a corrosive substance that can eat up your car metals and peel off car paint.

When Does Brake Fluid Burn?

When Does Brake Fluid Burn

When the temperature around the brake fluid is high, it becomes very flammable and can even catch fire. The flashpoint is the critical point of brake fluid; if the brake fluid goes above the flashpoint, it will vaporize and start burning.

Brake fluids are made of different types, and their flashpoint temperature varies; however, brake fluid is not flammable under average temperatures.

For example, 540-675°F is the temperature rate of ignite for most brake fluids. Therefore, among most brake fluid types, DOT3 is more flammable.

390-400°C is the igniting temperature for the glycol-based type of brake fluid. So be careful with the way you handle it and even other types of brake fluid because if they get in touch with high-temperature surfaces like the exhaust, it may cause a fire outbreak.

Also Read: Why Won’t My Brake Lights Turn Off (Causes & Fix)

How to Prevent Brake Fluid Burns?

It is a fact that brake fluid is dangerous and flammable. Therefore it requires careful handling. Here are some ways you can keep yourself and your car safe from the flammability of brake fluid.

  1. Keep the brake fluid away from electrical points and possible fire points.
  2. When you are working with brake fluid, always use protective gloves.
  3. Clean your skin immediately as it gets on your skin
  4. Do not keep brake fluid in an open container; always use a container with an airtight cap. And store them in an area that is neat and well dried.
  5. Ensure that the brake fluid you want to use is not contaminated or mixed with air to avoid chemical reactions that can cause burning.
  6. There are many types of brake fluid, and you can be tempted to mix them thinking it will help improve your brake system. PLEASE NEVER TRY THIS. You will end up creating a massive problem for yourself and your car.
  7. A low DOT rating causes fluid to boil and burn. Therefore avoid low DOT rating brake fluid.
  8. Overfilling the brake fluid reservoir can cause spillage, affecting the car section where the spillage occurs. So Just add a reasonable amount of brake fluid but avoid overfilling.
  9. Cleaner solvent contains chlorine, and when chlorine reacts with brake fluid, it causes burning. Therefore avoid spraying cleaning fluids around or within the brake fluid compartment.
  10. If you notice brake fluid leakage, try and fix it as soon as possible; if not, there could be an issue of accidental burn.

Is Prestone Brake Fluid Flammable?

Prestone brake fluid is a special fluid that lasts longer and provides better driving conditions. It is more temperature tolerant than DOT brake fluid because of its synthetic nature.

The Prestone brake fluid has more benefits than other brake fluids; for example, it prevents your car from overheating and helps your braking system be more effective without failure.

It also has a high flashpoint value making it significantly less flammable; in fact, the manufacturers clams it is non-flammable.

What Fluids Are Flammable in Automobiles?

Your car has many fluids that help increase its performance and sustain its functionality. Such fluid includes; windshield washer fluid, engine coolant, transmission fluid, and engine oil.

All these fluids have their unique properties and functions. They can also be flammable but are designed to be only explosive at very high temperatures when they are primarily in a gaseous state due to the high temperature.

However, under standard or average temperature, they are not flammable. It is essential to handle these fluids with great care because some can be toxic and corrosive.

Is Dot 3 Brake Fluid Flammable?

DOT 3 brake fluid is moderately flammable with a low flashpoint. DOT 3 is one of the brake fluid models that can be found easily in the market; it is glycol-based, amber in color, and can withstand different temperatures, whether cold or hot. It hardly solidifies or boils at any of these temperature conditions.

Is Dot 4 Brake Fluid Flammable?

DOT 4 uses glycol ether; they have a flashpoint of 210-375°F and burns at high temperatures. In addition, they burn quickly when compared to silicone-based brake fluid.

Is Dot 5 Brake Fluid Flammable?

DOT 5 is very flammable compared to others. During a collision, it can quickly ignite and start up a fire. In addition, it doesn’t work with moisture; it can get weakened by moisture and cause corrosion when mixed with moisture.

When Does Brake Fluid Catch Fire?

The brake fluid becomes flammable at very high temperatures, but it will catch fire if the temperature keeps going up and moves above the flashpoint. Though different brake fluids have various flashpoints, most brake fluids will ignite at the range of 540-675°F.

Also Read: Clunking Noise When Braking (Causes & Solutions)

Frequently Asked Questions – Is Brake fluid Flammable?

Is Brake Fluid Highly Flammable?

Yes, brake fluid is flammable. However, they are slow in burning. All the various brake fluid types are flammable, but they are way less flammable when compared with gasoline; they burn slowly. They are pretty faster in burning when compared to candle wax. The properties and components of a brake fluid need to be understood to know why it is flammable.

Is Dot 4 Brake Fluid Flammable?

Yes, DOT 4 brake fluid is flammable. DOT 4 uses glycol ether; they have a flashpoint of 210-375°F and burn at these high temperatures. In addition, they burn quickly when compared to silicone-based brake fluid.

Is Dot Three Brake Fluid Flammable?

DOT 3 brake fluid is moderately flammable with a low flashpoint. DOT 3 is one of the brake fluid models that can be found easily in the market; it is glycol-based, amber in color, and can withstand different temperatures cold or hot. It hardly solidifies or boils at any of these temperature conditions.

Is Brake Fluid Hazardous?

Yes, the constituent of brake fluid is very poisonous and dangerous. Therefore, brake fluid should be handled carefully, stored in a cool, dry place, and kept off children’s reach.

How Do Brake Systems Cause Fires?

Brake fluid will catch fire under high temperatures, a temperature above the flashpoint, and this temperature is rarely reached. However, if something wrong results in overheating or a heavy collision that may trigger this high temperature, the brake fluid may cause a fire.

What Happens if You Spilled Brake Fluid?

Brake fluid spillage can be catastrophic to the affected area of the car; this is because it can cause corrosion within the affected area. However, a prompt response by cleaning off the affected area can save the situation.

Conclusion – Is Brake fluid Flammable?

Brake fluid is flammable. However, they are slow in burning. All the various brakes types are flammable, but they are way less flammable when compared with gasoline but they are pretty faster in burning when compared to candle wax.

Brake fluid is essential for your brake and power transfer system. There are several types, and the flammability varies based on the constituents.

Brake fluid will burn under high temperatures and may ignite when the temperature is high above the flashpoint. Brake fluids are toxic and corrosive; therefore, it requires careful handling.

Scott Greene is a seasoned automotive technician for over 5 years and has been deep into advanced automotive diagnostics for a couple of years. He Loves writing about Automotive Diagnostics and Repair, Trouble codes, Buyer guides for various car parts and accessories, and lots more. 

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