DOT 3, DOT 4, and DOT 5.1 are all glycol-based brake fluids and are chemically compatible, but mixing them can change the boiling point and performance. Always check your owner's manual for the correct brake fluid type to ensure proper maintenance. You must NEVER mix DOT 5 (silicone-based) brake fluid with DOT 3/4/5.1 fluid because they do not blend and can form gel-like sludge that can cause brake failure.
If you have questions about brake fluid, talk to our service advisors or see our Brake Repair in Ann Arbor page for details about our brake repair services.