Different Types of DOT Fluids Used in Automobiles

The operation of your braking system is essential for your and others' safety. If your vehicle's braking system is a hydraulic system, then it means you need brake fluid to carry out its functions. Without brake fluid, also referred to as DOT fluid, it helps your car come to a complete stop. DOT fluid is one of the most popular forms of brake fluid used in cars, SUVs, and trucks today. There are different grades or categories of DOT fluid, and it can be confusing since they're classified with numbers. Here are the differences between each type of DOT fluid:

  • DOT 3 - It is a glycol-based brake fluid with the lowest boiling point. It is the most basic and cheapest option.
  • DOT 4 - Most cars outside of the US use this fluid. DOT 4 has a higher boiling point than DOT 3, making it more expensive.
  • DOT 5: DOT 5 is more distinctively different than DOT 3 & 4 because it is silicone-based. Some of them have a purple hue, and it is priced similarly to DOT 4. Since it is silicone-based, it doesn't absorb water like other forms of brake fluid.
  • DOT 5.1: This brake fluid is glycol-based that is fainter in color. It is similar to DOT 4 but with the strength of DOT 5.

The main distinctions between all these fluids (DOT 3, DOT 4, and DOT 5.1) are their boiling points and chemical composition. When topping off your vehicle with brake fluid, please make sure you use what the manufacturer recommends. If you are unsure of which DOT fluid your vehicle takes, please check the owner's manual for specifications. 


For all your brake maintenance and repair needs, please bring your car to the certified technicians at GermanTech MotorWorks LLC.