Which is better DOT 3 or DOT 4?
Matthew Cannon
Updated on January 23, 2026
DOT 4 brake fluid. The primary differences between the two include the following: DOT 3 brake fluid will absorb less water than DOT 4 from the air over time, meaning you'll need to have your fluid changed less frequently. DOT 4 brake fluid has higher dry and wet boiling points, making it safer for higher temperatures.
What happens if you use DOT 4 brake fluid instead of DOT 3?
Typically a DOT 4 brake fluid will suffer a boiling point drop of 50% once it takes in 2% moisture while a DOT 3 brake fluid would only lose 25% of its boiling point at 3% moisture contamination although it takes in moisture at a faster rate.Which brake fluid is best?
- Editors Pick: Bosch ESI6 Brake Fluid. If your vehicle uses DOT 3, DOT 4, or DOT 5.1 brake fluid, the Bosch ESI6 brake fluid will work for you. ...
- Prestone Synthetic Brake Fluid. ...
- Motul RBF 600 Synthetic Brake Fluid. ...
- Castrol SRF Racing Brake Fluid. ...
- ATE TYP 200 Brake Fluid.
Can we mix DOT 3 and 4 brake fluid?
Yes. DOT 3 and DOT 4 are both glycol ether based, and will mix just fine. DOT 4 has a higher boiling point, so depending on the application, it may be necessary to use that instead of DOT 3.Does brake fluid go bad?
Here is the short answer: Yes, brake fluid can go bad. Brake fluid absorbs moisture, which reduces its performance. For that reason, it's best practice to change brake fluid every two years.The Difference between DOT 3 and DOT 4 Brake Fluids
Can DOT 3 be used for power steering?
Can you use DOT 3 instead of power steering fluid? No, because DOT 3 is glycol-based and will eat away at rubber seals while causing damage to the power steering pump due to a lack of lubrication.When should I use DOT 4 brake fluid?
#4 – Boiling CapacityDOT 3 braking fluid contains both a great wet boiling capacity and dry boiling capacity. This means the fluid will work well when it's exposed to water and the open air. DOT 4 braking fluid is best when it comes to a dry boiling capacity. Unfortunately, its wet boiling capacity is not so great.