Brake fluid Audi A4 B9 (2015–2023) — DOT4 specification
Brake fluid for Audi A4 B9 (2015–2023) — required specification, boiling points, system volume, and approved brands.
Caractéristiques techniques
| Parameter | Value |
|---|---|
| Marque / Modèle | Audi A4 B9 |
| Années de production | 2015–2023 |
| Spécification du liquide | DOT4 |
| Point d’ébullition sec | 230°C |
| Point d’ébullition humide | 155°C |
| Volume du système | 600 ml |
| Intervalle de remplacement | 30 000 km / ans |
Marques approuvées
Audi/VW DOT4, ATE SL.6, Liqui Moly DOT4
Why Brake Fluid Must Be Changed Regularly
Brake fluid is hygroscopic — it absorbs moisture from the air over time. As moisture content increases, the boiling point drops significantly. When the fluid boils under heavy braking, vapour bubbles form and the pedal goes to the floor (vapour lock). Audi requires DOT4 with a dry boiling point of at least 230°C.
How to Check Brake Fluid Condition
- Test strips — dip a strip in the reservoir; colour indicates moisture content
- Electronic tester — measures boiling point directly (most accurate)
- Visual inspection — dark/brown fluid indicates it must be replaced (fresh fluid is amber/clear)
Questions fréquentes
What brake fluid does Audi A4 B9 use?
DOT4 specification. Point d’ébullition sec: 230°C. Volume du système: 600 ml. Marques approuvées: Audi/VW DOT4, ATE SL.6, Liqui Moly DOT4.
How often should I change brake fluid in Audi A4 B9?
Every 30 000 km or every ans — whichever comes first. This is a safety-critical service.
Can I mix different DOT grades?
You can mix DOT 3 and DOT 4 in an emergency, but never mix DOT 5 (silicone-based) with DOT 3/4 (glycol-based). Always use the correct specification: DOT4.
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