Should I use DOT 3 or 4 brake fluid?
When it comes to maintaining your vehicle's braking system, the type of brake fluid you use is crucial. The two most common options are DOT 3 and DOT 4 brake fluids. Choosing the right one can ensure your brakes function safely and effectively. In this article, we'll explore the key differences between DOT 3 and DOT 4 brake fluids to help you make an informed decision.
What is Brake Fluid?
Brake fluid is a hydraulic fluid used in a vehicle's braking system. It is responsible for transmitting the force applied to the brake pedal to the brake calipers, causing the brake pads to press against the brake discs or drums, slowing or stopping the vehicle. Brake fluid must be able to withstand high temperatures and pressures without boiling or becoming compressed, ensuring consistent and reliable braking performance.
DOT 3 vs. DOT 4 Brake Fluid
The main difference between DOT 3 and DOT 4 brake fluids lies in their boiling points, which are a crucial factor in determining their suitability for different driving conditions and vehicle types.
Boiling Point
DOT 3 brake fluid has a lower boiling point, typically around 401°F (205°C) for the dry boiling point and 284°F (140°C) for the wet boiling point. DOT 4 brake fluid, on the other hand, has a higher boiling point, with a dry boiling point of around 446°F (230°C) and a wet boiling point of 311°F (155°C).
The higher boiling point of DOT 4 brake fluid makes it better suited for vehicles that experience more demanding braking conditions, such as heavy-duty trucks, high-performance cars, or vehicles used for towing or hauling heavy loads.
Hygroscopic Properties
Both DOT 3 and DOT 4 brake fluids are hygroscopic, meaning they absorb moisture from the air over time. This can lower the boiling point of the fluid, reducing its effectiveness and potentially leading to brake fade or even complete brake failure in extreme cases.
DOT 4 brake fluid has a slightly higher moisture absorption rate compared to DOT 3, but it also has a higher boiling point, making it more resistant to the effects of moisture contamination.
Choosing the Right Brake Fluid
When deciding between DOT 3 and DOT 4 brake fluid, consider the following factors:
- Vehicle Type: If you have a high-performance or heavy-duty vehicle, DOT 4 brake fluid is generally the better choice due to its higher boiling point.
- Driving Conditions: If you frequently drive in mountainous areas, tow heavy loads, or engage in aggressive driving, DOT 4 brake fluid may be the safer option to prevent brake fade.
- Maintenance Schedule: DOT 4 brake fluid should be replaced more frequently than DOT 3, as it is more susceptible to moisture contamination.
Ultimately, it's essential to consult your vehicle's owner's manual or a qualified mechanic to determine the recommended brake fluid type for your specific make and model. Using the wrong brake fluid can lead to serious safety issues and potentially damage your vehicle's braking system.
What happens if I put DOT 4 instead of DOT 3?
DOT 4 has a higher boiling point than DOT 3. You can use DOT 4 where DOT 3 is called for, but not the reverse. Using DOT 3 in a DOT 4 brake risks boiling the brake fluid.
What vehicles use DOT 4 brake fluid?
DOT 4 is used in some euro and domestic vehicles. DOT 4 Plus is used in Mercedes and Volvo. DOT 4 Low Viscosity is used in some BMW models.
How often should I change my DOT 4 brake fluid?
every two years
YOU SHOULD REPLACE BRAKE FLUID EVERY FEW YEARS
And the best way to find out how often to change brake fluid is to follow your manufacturer's recommendations. Some manufacturers say you should replace your brake fluid every two years. Others recommend every three years, or every 45,000 miles.
Can I use DOT 4 brake fluid in older cars?
Choosing the Best Brake Fluid for Your Classic Car
We recommend DOT 3 or DOT 4 because these brake fluids are glycol-based and hygroscopic. They are the kindest on your braking system.
Can you mix DOT 3 and DOT 4 brake fluid together?
3 dot 4 446. And dot 5 5.1 up to 500 fahrenheit that by the way dot. 5 is not mixable it's a different uh. Different type of brake fluid. So you can't mix that only dot 3 and dot 4 can be mixed.
What are the disadvantages of DOT 3 brake fluid?
The fact that DOT 3 brake fluid is hygroscopic—that is, it can draw moisture over time—reduces its boiling point, thus reducing its efficiency. The collected moisture can cause rusting inside the braking system and eventually failure.
Is it okay to mix old and new brake fluid?
Basically, not recommended. If either fluid as glycol base and both passed DOT approved, no major functional problem. However, in performance-wise not become a average of 2 but, lower side kept. Therefore, refrain from mixture of fluid but, replacement of whole volume is recommended.
What is the best brake fluid?
The 10 Best Brake Fluids to Maintain the Safety of Your Brakes
- ShopPro DOT 3 Brake Fluid 32 ounce.
- Prestone DOT 3 Brake Fluid 32 ounce.
- Pentosin DOT 4 Brake Fluid 1 liter.
- Lucas Oil DOT 3 Brake Fluid 32 ounce.
- Valvoline DOT 4 Brake Fluid 32 ounce.
- Prestone DOT 4 Brake Fluid 12 ounce.
- Shop Pro DOT 3 Brake Fluid 1 gallon.
How do I know if I need DOT 3 or DOT 4 brake fluid?
DOT 4 brake fluid has higher wet/dry boiling points than DOT 3, making it a better choice for higher temperature braking applications, like in high-performance vehicles.
What vehicle is DOT 3 brake fluid used for?
DOT 3 brake fluid is typically utilized in standard vehicles like cars, SUVs, and trucks. It's adequate for everyday driving and can endure challenging conditions like elevated temperatures and forceful braking.
