3 Points to Take Note When Comparing between DOT 3 vs DOT 4 Brake Fluid

The brake fluid is the lifeblood of the braking system. It keeps the braking components lubricated so that they respond promptly when you press the brake pedal. With the help of the fluid, the piston can comfortably compress the rotors to slow down the vehicle. DOT 3 and DOT 4 are two most common types used in automobiles. If you are looking for the right fluid for your car, a comparison of DOT 3 vs DOT 4 brake fluid will help you to decide better.

What Is the Difference between DOT 3 vs DOT 4 Brake Fluid?

DOT 3 is the most common and popular brake fluid type of truck and cars. DOT 4 is also gaining momentum due to its compatibility with anti-lock braking system and traction control. The first one is the standard, low-cost option for average cars where there is little chance for the drivers to engage in aggressive braking actions. But, automobiles like racing cars and police vehicles that need frequent vigorous braking use DOT 4 fluid. Let’s find out some more points of difference between DOT3 vs DOT4:

dot 3 vs dot 4
A comparison will help you take a better decision. Source: DailyDriven

1. Boiling Point

The major difference between DOT 3 vs DOT 4 is the boiling point – their tenacity to absorb water. DOT 3 is more prone to assimilate water because it has a lower boiling point. For this reason, it boils easily under hard and rough braking, which could ruin the braking components and cause subpar braking performance. For this reason, the DOT 4 fluid can easily replace DOT 3 but the second one should not be used as an alternative to the DOT 4 type until it’s absolutely necessary.

2. The Chemical Structure

Another slight difference between DOT 3 vs DOT 4 brake fluid is their chemical components. DOT 3 has a blend of ether and polyalkylene glycol whereas a mixture of glycol and borate creates the DOT 4 fluid. The glycol-ether blend holds very well in hot and wet conditions, which is perfect for regular vehicles where the brakes get heated up easily. On the other hand, DOT 4’s chemical ingredients that show a high level of water tolerance and stability under high temperatures.

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3. Boiling Capacity

DOT 3 is the winner in this comparison section between DOT 3 vs DOT 4 brake fluid. It functions well in both water and open air because it has both wet and dry boiling capacity. DOT 4 has an excellent dry boiling capacity but it does not work well in water.

Which one should you choose? DOT 3 or DOT 4 brake fluid? Well, the first one is the best option if you are driving a standard vehicle. However, if it’s a racing car or you like rough driving, DOT 4 will take better care of the braking components.

dot 3 or dot 4 brake fluid
DOT 4 will take better care of braking parts.

Watch the video below to see the difference between Dot 3, 4, 5 and 5.1 brake fluid

Are There Any Cautions to be Aware of?

Yes, there are a few things to be aware of. Both fluid types eat paint, so don’t spill them on the car body. Also, they can react badly if mixed with other fluids used in a vehicle.

You should keep the fluids in tightly sealed containers. The moisture in the air degrades their chemical components. So, it’s not safe to use the brake fluid from an open bottle.

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