What’s the Difference Between Dot 3 Vs. Dot 4 Brake Fluid 

Brake Fluid

A vehicle’s brake system works as a hydraulic system, which means it’s dependent on brake fluid. It’s not possible to understand all of the brake fluid. Every car needs this brake fluid, but it doesn’t mean we know the meaning of numbers and letters. Most drivers don’t understand every brake fluid contains its ratings.

And they affect your vehicle’s performance during driving. However, Dot 3 vs. Dot 4 brake fluid, what’s the difference, you are coming to know. Understanding what brake fluid ratings mean and what they can help you make the best long-term care decisions. To be clear about both fluids, you must stay with us.

How Brake Fluid Works: 

Before explaining the differences, it’s essential to understand what brake fluid does. It gives an idea of how several ratings impact the brake system’s performance.

Many vehicles utilize a hydraulic braking system. During pressing the brake pedal, this pressure sends the brake fluid into calipers that squeeze the pads into the rotors. Depending on your force, rotors and pads can make massive friction so your car can stop more quickly.

Brake fluid is essential, and you need to change the brake fluid frequently. The reason is that over time this fluid will be poor. Also, it can consume moisture to prevent brakes from performing correctly. Inadequate fluid can destroy your brake system. Ultimately, you should maintain your fluid for safe driving.

Are you wondering about insufficient moisture? Don’t worry; because it’s simple, fresh brake fluid contains high boiling points, producing high temperatures during braking.

Dot 3 Vs. Dot 4 Brake Fluid

Dot 3 Vs. Dot 4 Viscosity: 

Although Dot 3 and Dot 4 are both glycol-based fluids, under the right situations, Dot 3 has a longer life than Dot 4. Glycol-based liquids are not typical; they blend ten different substances. The viscosity of Dot 4 is more than Dot 3, and it can maintain its fluidity at higher temperatures.

Therefore, viscosity is the measure of liquid resistance to the stream. Subsequently, Dot 4 brake fluid shows high stability and tolerance under extreme temperatures because of its high viscosity.

What Are Brake Fluid Ratings, And What Do They Mean?

To know the brake fluid dot meaning and ratings read this portion attentively.

Dot 3 Brake Fluid Meaning And Ratings: 

Based on the brake fluid’s boiling point, the ratings are generated. There are two boiling points: dry and wet boiling points. Traditionally, these boiling points are rated as Dot 3 or Dot 4 brake fluid. Here the DOT stands for the Department of Transportation, which determines the ratings.

Typically, while comparing Dot 3 vs. Dot 4, Dot 3 has a 401°F dry boiling point and 284° wet boiling point. There is no standard formula for many brake fluids; it’s an estimated boiling point. Even so, the exact boiling points may vary. Simple Dot 3 brake fluids normally exceed these values. Dot 3 brake fluid typically contains 80% glycol ether base that contributes to water sucks.

Dot 4 Brake Fluid Meaning and Ratings: 

Dot 4 fluids have higher dry and wet boiling points, which are needed in brake systems to generate extra heat. Moreover, Dot 4 brake fluid can absorb moisture more quickly than Dot 3. That’s why you need to change this fluid regularly.

Additionally, Dot 4 fluid has 50-65% glycol ether based with 20 to 30% Borate Ester that helps prevent the liquid from boiling. Therefore, this Dot 4 fluid can absorb 3.7% water 20% faster than Dot 3.

When testing Dot 3 vs. Dot 4, brake fluid, lifespan, and boiling point are the most critical distinctions between categories. You need to replace Dot 4 more frequently than Dot 3. Furthermore, there are ratings of Dot 5 and Dot 5.1 brake fluid, but they are less common.

These fluids differ if you compare Dot 3 vs. Dot 4 vs. Dot 5. Dot 5 is silicone-based fluid, and Dot 5.1 contains 70% silicone. That said, always using a vehicle manufacturer with the same rated brake fluid is the best idea.

Differences Between Dot 3 vs. Dot 4 Brake Fluid: 

Most auto manufacturers use two types of brake fluid. The two brake fluids are Dot 3 and Dot 4 brake fluid. Below have some critical differences between these two categories of fluid:

Boiling Point: 

With a higher boiling point Dot 4 brakes come. Notably, if you are driving your car with heavy braking, Dot 3 could quickly boil. For this reason, you can face the above complications.

Generally speaking, if you want to do many things regularly, dot 4 is more reliable because it doesn’t boil quickly. Autocross vehicle owners at the track will need high boiling point brake fluid.

Chemical Components:

Eventually, Dot 3 brake fluid comes from polypropylene and ether. And this mixture makes a powerful brake fluid that can operate in wet and heated conditions.

In contrast, Dot 4 brake fluid comes from glycol and borate. Ultimately, this mixture creates a more stable brake fluid that can handle extreme temperatures.

Boiling Capacity: 

Regardless, Dot 3 brake fluid has both wet and dry boiling capacity. That means this brake fluid can work comfortably in water and open air.

On the contrary, Dot 4 brake fluid can work well in dry boiling capacity. Unfortunately, this fluid can’t work well in wet boiling capacity.

Car Types

Generally, Dot 3 is best for an average economy vehicle because cars need low stopping energy. For police cars, racing, and motorcycles, drivers use Dot 4 because they all brake more aggressively and frequently. Follow the car manufacturer’s suggestion to know what fluid you need to use.


It would help if you bought brake fluid, depending on your car’s manual capacity. If your vehicle needs Dot 4 brake fluid, you should buy it. But what’s the actual Dot 4 brake fluid price? Correspondingly, the Dot 4 brake fluid price is $10 to $12. And the Dot 3 brake fluid price is $9 to $10.

can you put dot 4 in a dot 3 system

FAQs (Frequently Asked Questions): 

Q. Which brake fluid is better, Dot 3 or Dot 4?

Dot 4 brake fluid is better. Their primary differences are that Dot 3 absorbs less water and Dot 4 absorbs much water from the air. Adequately, Dot 4 brake fluid contains higher wet and dry boiling points, making it safe for high temperatures.

Q. What is the advantage of DOT 4 brake fluid?

There are many advantages of Dot 4 brake fluid. For example, it provides consistent and safe brake performance under severe braking pressure. Likewise, it also has excellent corrosion protection and can reduce leakage, fluid losses, and more.

Q. Can you mix Dot 3 vs. Dot 4 brake fluid?

You can mix Dot 3 vs. Dot 4 brake fluid. It’s because they both are glycol and ether-based; if you mix it, It’s okay. Hence, Dot 4 has a higher boiling point. So, depending on the application, it’s best to use Dot 4 brake fluid instead of Dot 3.

Q. Can you put dot 4 in a dot 3 system?

 Yes, you can use Dot 4 in a Dot 3 car. Usually, the real difference between them is how hot they can get before boiling. Generally, Dot 4 isn’t harmful to the Dot 3 system. But never use Dot 5 brake fluid with them because it’s completely different.

Final Word: 

Finally, this is the accurate Dot 3 vs. Dot 4 brake fluid contents. Subsequently, Dot 3 fluid can absorb water more efficiently than Dot 4. Possibly, it is more quickly to boil under heavy braking, and it affects the braking performance.

This is the reason for not using Dot 3 fluid in aggressive cars. Subsequently, Dot 4 has high stability and tolerance under extreme temperatures. Ergo, it helps in the proper functioning of the total braking system. At last, we are trying to cover all information about this topic. We hope you get some correct information from here.


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I am Engr. Z Eusuf Lubricant Specialist, Mechanical Engineer & has been working with engine lubricants for a long time and knows what makes them work best. I can help you find the right oil for your needs, and I have tips on how to keep your engine running at its best.