DOT ratings at a glance
DOT 3, DOT 4 and DOT 5.1 are all glycol-based and can be mixed with each other. DOT 5 is silicone-based and should never be mixed with the others. For the full explanation, read our brake fluid guide.
| Fluid | Base | Min. dry boiling point | Min. wet boiling point |
|---|---|---|---|
| DOT 3 | Glycol | 205 °C / 401 °F | 140 °C / 284 °F |
| DOT 4 | Glycol | 230 °C / 446 °F | 155 °C / 311 °F |
| DOT 5.1 | Glycol | 260 °C / 500 °F | 180 °C / 356 °F |
| DOT 5 | Silicone | 260 °C / 500 °F | 180 °C / 356 °F |
Minimums set by US standard FMVSS 116. “Wet” means after the fluid has absorbed moisture.
Frequently asked questions
No. Despite the similar name, DOT 5.1 is glycol-based like DOT 3 and 4. DOT 5 is silicone-based. Don’t confuse the two at the parts counter.
Generally yes, since DOT 4 meets a higher boiling-point standard and is glycol-based. Go with what your owner’s manual allows.