DOT 4 is the most commonly specified brake fluid for modern vehicles, offering higher boiling points and a greater safety margin than DOT 3. Its improved stability under heat makes it suitable for both factory fill and aftermarket use. DOT 4 remains fully compatible with DOT 3, making it a versatile choice across a wide range of braking systems. All DOT 4 fluids have a minimum dry boiling point of 230°C/446°F, a minimum wet boiling point of 155°C/311°F and a maximum viscosity of 1500 cSt at –40°C.
