Why Is My Brake Fluid Green?

Why Is My Brake Fluid Green? Green fluid means that your fluid is leaking somewhere, and you need to take steps to stop the leakage immediately. 

As we all know, motor oil, which is brake fluid, may leak out of your vehicle after a certain period of usage; while it leaks, you may feel the difference in the color of the fluid, and it becomes tough to distinguish between the two. 

Usually, you will see brake fluids come in clear color, and when it leaks, it turns to green color. But have you ever wondered why brake fluid turns green during leakage? So here we will provide you with every detail about it. 

In this article, you will learn: 

  • Why is brake fluid important? – Role of brake fluid
  • What is the standard life of brake fluid? 
  • Why is green brake fluid a cause of worry? 
  • What to do if you see green brake fluid? 
  • Different types of Brake Fluid 

Why Is My Brake Fluid Green

Why Is Brake Fluid Important?

Before we get into the details about the color of brake fluid, it is essential to know what it is and why it is important? 

For the proper functioning of the brake system of a vehicle, brake fluid is an important element. It is a liquid chemical solution, a typical hydraulic fluid most used for hydraulic brakes and clutch in a car. 

It is majorly used for turning the force into pressure and for amplification of braking force. In simple terms, when a person puts their foot on the brake pedal, the right brake fluid transfers this force into pressure to both brakes to stop the vehicle. 

Incompressible Fluid

This pressure happens as fluids are incompressible. It is important to get the correct brake fluid that has certain features and meets the quality standards of the car. 

For a constant and reliable braking system, brake fluid maintains a constant viscosity to maintain the right temperature. Brake fluid is specially designed to save metal parts of the brakes to ensure the vehicle has an efficient braking system. 

Regular Maintenance

You need to check brake fluid often as you check other car fluids; it is as important as other parts to protect your car from damage due to an inefficient braking system. 

The problem starts when the brake fluid level lowers down, it is because of the leakage. The leakage of brake fluid happens due to less hydraulic pressure, resulting in loss of braking ability. For better and safe operation of your vehicle, it is critical to take care of brake fluid. 

Why Is My Brake Fluid Green

Does Brake Fluid Go Bad Or Needs To Be Changed? 

Yes, it is a fact that over time, brake fluids need to be changed. It is important to change the brake fluid as recommended on the cars’ manual, and it is also crucial to ask a technician to change the brake fluid. 

Here are few reasons why brake fluid loses its effectiveness: 

# Brake Fluid is Hygroscopic 

Although it is a fancy word, this feature matters a lot. It means that the fluid absorbs moisture from the air. No matter how closed is your braking system, you cannot avoid small amounts of moisture that mix with the fluid. This usually happens when you leave the brake fluid cap open for a longer time than it is required. Even a tiny amount of water contamination leads to losing the effectiveness of the brakes. 

# Corrosion 

Another reason why there is a need to change the brake fluid is corrosion in the braking system. Brakes fluid is important as it includes corrosion inhibitors that allow the braking system to work. When these inhibitors break down, it leads to metal corrosion. 

Also read: Do they use special brake fluid for Harley Davidson bikes?

What Is the Standard Life of Brake Fluid?

Typically brake fluid should be able to work properly for around two years.

The brake fluid runs between the brake lines of the master cylinder and wheels of the car. If you press the brakes harder than required, the brake fluid contaminates more quickly than usual. 

But even with regular brake use, the fluid gets contaminated over time. The brake fluid can absorb moisture quickly, even from microscopic brake lines. It is also overheating and aging leads to bad brake fluid. 

When your brake fluid ages, the color changes, either green or golden, and it is a warning sign that you need to change the brake Fluid. 

Why Is My Brake Fluid Green

Why Is Green Brake Fluid a Cause of Worry?

When your clear brake fluid turns into green fluid, it is a sign of changing the fluid. The green color depicts that some algae kind of chemical is present in the brake fluid, but if the color is green and clear, it may work for some time but still consider it a sign of changing the brake fluid. 

Green brake fluid means it is contaminated brake fluid, and it may destroy the braking system or lose control of the brakes. 

When the green fluid turns into black, it means it is more contaminated, and it clearly shows that you need to change the fluid to avoid any accidents. 

Green fluid is the first sign of changing the brake fluid. 

What To Do if You See a Green Brake Fluid?

Doing a regular vehicle inspection, either by yourself or a mechanic, saves you from seeing a green brake fluid. Also, a standard service must include changing brake fluid. If you see a green fluid, visit a mechanic and ask for an immediate replacement to avoid further signs of contaminated brake fluid. If you want to do it yourself, get a baster that will allow you to remove the old fluid from the reservoir and then allows you to pour new brake fluid. It is important to repeat the process till you get clear and yellow brake fluid. Having green brake fluid will not cause any damage right away, but it is important to resolve it as soon as you can. 

Why Is My Brake Fluid Green

Different Types of Brake Fluid 

Once you know that you need new brake fluid, you must know which is the right type of brake fluid for your vehicle. 

Usually, there are three types of brake fluids you will get in the market, they are the following: 

# DOT 3 

It is a standard and popular brake fluid, and even most of the cards are compatible with DOT 3 brake fluid. The types of brake fluids are classified based on their boiling points, and a boiling point is a saturation point when the fluid starts vaporization. 

This brake fluid type has an average boiling point of 401 FH in dry conditions and 284 FH in wet conditions. 

# DOT 4 

This type of brake fluid is specially designed for heavy-duty performance; it has a boiling point of 446 FH in dry and 311 FH in wet conditions. 

DOT 4 brake fluid is important for vehicles used in uphills. When there are sudden drops, they increase temperature, so it is important to have a brake fluid that has more resistance power to hold heavy pressure. 

It is important to know that you should not mix DOT 3 and DOT 4; although few cars are compatible with both types, it is still recommended to check the owner’s manual before you pour the one. 

# DOT 5 

It is a silicon-based brake fluid that is majorly used in military cars or antique vehicles. They have the highest boiling points at 500 FH in dry conditions, and DOT 5 is water-resistant brake fluid. Also, one should never swap or mix DOT 5 with DOT 3 or DOT 4. 

Why Is My Brake Fluid Green

How do you know if you have bad brake fluid? 

If you have seen bad brake fluid before, you can easily notice it at first glance. The bad brake fluid sticks like a sore thumb. 

New drivers usually don’t notice the change of color of the brake fluid, so in that case, it is essential to look into the brake pedal at the time of braking. If the brake fluid is bad, the brake system will not run smoothly. 

The pedal gives you a feeling of softness or spongy, or it may require hitting the brakes multiple times when you need them. 


# What color is bad brake fluid? 

As we know, the new brake fluid is clear and yellowish, and if the brake fluid turns green, it is a sign that some algae are present in the brake fluid; it clearly shows that you need to change the brake fluid. Further, when it turns black or brown, it is bad brake fluid and immediately flush the old fluid and pour the fresh one. 

# What color should your brake fluid usually be? 

A fresh and normal brak fluid is usually transparent with a hint of yellow color. 

Why Is My Brake Fluid Green

# Can you mix green and red brake fluid? 

No, it is not recommended to mix any two types of brake fluid as they have different boiling points. 

# What color is DOT 4 brake fluid? 

DOT 4 comes in amber color, just like a light beer. 


Often, drivers don’t notice the impact of green brake fluid the car has, but it is important to keep an eye on the brake fluid if its color changes. Make sure you change the brake fluid when it turns green, as it prevents further contamination of the fluid. 

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Sean Mendez

Hi, I am Sean, a self-confessed petrolhead. I live in Boise, Idaho with a busy family of four and our energetic Labrador retriever. Thank you for visiting my website. You can find my email on the contact page.

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