Learn How Can You Mix DOT 3 And DOT 4 Together?

In many current cars and trucks, DOT 3 and DOT 4 braking fluids are used everywhere.

Both types of fresh brake fluid operate well, with DOT 3 being used more in newer vehicles or for high performance and DOT 4 being utilized more in high-performance automobiles, which helps keep the moisture.

But, Can You Mix DOT 3 and DOT 4 Together? Yes, you can mix DOT 3 and DOT 4 brake fluids. Both DOT 3 and DOT 4 are glycol-based brake fluids that can be combined; however, it’s typically advisable to stick with the manufacturer’s recommendation.

If you are still confused, you can read the following article to understand your curiosities better; what is hydraulic fluid and synthetic fluid, the difference between two brake dot fluids, and which one is the better glycol-based brake fluid; know them all!


What Is The Difference Between DOT 3 And DOT 4 Brake Fluid?

The actual boiling point of DOT 3 and DOT 4 braking fluids differs significantly. DOT 4 brake fluid contains a higher boiling point in wet and dry conditions, making it better suited for higher performance and keeping the moisture for too long.

DOT 3 and DOT 4; The Glycol-based brake fluids are used in your braking system. Because they are hygroscopic and collect water from the air, caution must be exercised when keeping and refilling possibly contaminated fluids of the brake pad.


Distinguishing DOT 3 And DOT 4 Brake Fluid

  • Compared to DOT 4, DOT 3 contains a lower boiling point. Therefore, it performs better, mainly when the brake pedal is pressed vigorously.
  • For ordinary driving, DOT 3 is sufficient, and the higher-performing DOT 4 is unnecessary.
  • The dry boiling point of DOT 3 is 401 degrees Fahrenheit, while DOT 4 is 446 degrees Fahrenheit.

The greater the fluid’s boiling point, the better the performance.

When brakes are utilized frequently, such as when going down a steep slope or doing a lot of city driving, they can become boiling.

Each time the brakes are utilized, the dot brake fluid must be able to handle the heat range, or the brakes will fail.

The brakes of most average drivers will never heat up to the point where higher-performance regular brake fluid is required, but it can be applied if you feel it is correct.


Can You Mix DOT 3 And DOT 4 Together?

Yes, you can blend DOT 3 and DOT 4 brake fluid. Because both of these brake fluids are glycol-based, they’re compatible with each other.

It is not recommended to fill your automobile with DOT 3 if it comes with DOT 4 from the factory, but the other way is acceptable.

If your car came with DOT 3 and you know you’ll be towing a trailer or driving up steep slopes frequently, we strongly advise you to replace it with DOT 4 fluid.


Which One Is The Better Brake Fluid Between DOT 3 And DOT 4?

DOT3 is the more popular of the two brake fluids, but DOT4 is swiftly catching up due to its compatibility with typical traction control and anti-lock braking systems.

DOT 4 has higher boiling points, making it better for many applications; even though it is often more expensive, it is worth acquiring instead.

Although both are glycol-based braking fluids, DOT 4 has a more excellent boiling point. When performance is required, or when the brakes are used more frequently than usual, the higher boiling point is beneficial.

For everyday driving, DOT 3 is enough. When more performance is required, DOT 4 is the best choice.


What Is A Boiling Point Of Brake Fluids?

The brake fluid heats up quickly when you drive your car aggressively in the hills or with a trailer. If it gets too hot and starts to boil, you’ll lose control of your vehicle, which is the last thing you want to happen on a slope with a trailer.

As a result, having as high a dry and wet boiling point as possible is necessary.

When the braking fluid contains water, you can get a wet boiling point; when the brake fluid does not contain any water, the dry boiling point is determined.


Can You Mix Two Brake Fluid?

Yes, multiple brands of brake fluid can be mixed, but they must be of the same grade. When brake fluids of similar grades, such as DOT 3 and 4, are mixed, the worst that can happen is; that it’ll create a brake fluid with a lower boiling point.


Frequently Asked Questions

Can You Mix DOT 3 And DOT 5 Fluid?

DOT 5 brake fluid can only be mixed with more DOT5 brake fluid. That’s because DOT 5 is the only silicone brake fluid available; the rest are glycol-based.

Using the wrong brake fluid in your car can result in poor brake performance or even lock up your brakes and cause brake failure.


What Happens If I Mix DOT 3 And DOT 4 Brake Fluid?

Suppose you mix DOT 3 and DOT 4 brake fluid; the vehicle will not act suspiciously. Both brake line fluids are glycol-based, and mixing them is safe for their chemical structure.


What Are The Boiling Points Of DOT 3, DOT 4, And DOT 5.1 Brake Fluid?

The dry boiling point for DOT 3 is 205°C or 401°F, the dry Boiling point of DOT 4 is 230°C or 446°F, and the dry Boiling point of DOT 5.1 is 260°C or 500°F.


What Is The Advantage Of Using A DOT 3 Brake Fluid?

DOT3 contains a higher boiling point, so It’s consistent and provides safe braking performance even when the brake system pressure is high. DOT 3 reduces leakage so that the loss of fuel will be minimum. 

It has excellent corrosion resistance while braking. As a result, it extends the life and reliability of brake system components.


What Happens If You Mix Old fluid with New Brake Fluid?

You can mix the old fluid with the new braking fluid using the same types. For example, you can mix DOT 3 and DOT4 fluid as they are both glycol-based fluids. But you can not mix DOT3 brake fluid and DOT 5 brake fluid.


It’s Better If You Know

If you are still wondering, can you mix DOT 3 and DOT 4 together or not? The quick answer is yes if you have a vehicle requiring DOT 3 or DOT 4.

While dot3 and dot4 can be mixed, it usually is advisable to use the brake fluid advised by the manufacturer for the braking system.

Some drivers will use DOT 4 braking fluid more than DOT 3 fluid since it performs better, which is a conventional brake fluid, and these are glycol fluid, but it is unlikely to be required in typical driving situations.

Higher-performance synthetic brake fluid, such as DOT 5.1, and Dot 5 silicone fluid, is not interchangeable with other varieties.

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