Which brake fluid type has the highest boiling point?

The correct answer is based on the boiling points of various types of brake fluids, which are classified under the Department of Transportation (DOT). DOT 5 brake fluid is a silicone-based fluid and is known for its high boiling point, which can range from 260°C (500°F) or higher. This characteristic makes it suitable for high-performance applications where brakes can overheat, ensuring more consistent braking performance under extreme conditions.

In contrast, the other types of brake fluids, such as DOT 2, DOT 3, and DOT 4, have lower boiling points, making them less suitable for scenarios where high heat is produced. For example, DOT 3 typically has a dry boiling point of around 205°C (401°F), and DOT 4 has a higher boiling point than DOT 3 but is still significantly lower than DOT 5. DOT 2 brake fluid is less common and similarly has low boiling point characteristics.

Thus, DOT 5 stands out as the fluid with the highest boiling point, making it ideal for high-stress braking systems while maintaining more stable performance under heat-related challenges.