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How we reviewed this product: we studied the manufacturer's specifications, materials, included parts and warranty terms, read owner feedback where available, and compared it with similar products. We did not run our own lab tests.
Castrol's React SRF is a famous racing fluid. React Performance DOT 4 is the step below: a high-boiling "Super DOT 4" for fast road cars and hard driving, without SRF's racing focus.
Quick verdict
- Best for: performance road cars, towing, mountain driving and occasional track days.
- Type: synthetic glycol ether and borate ester DOT 4.
- Strengths: high boiling points, corrosion protection, broad compatibility.
- Watch out for: a "Low Temp" React fluid also exists; do not confuse the two.
Key numbers (Castrol data)
- Dry (ERBP) boiling point: at least 260 °C (500 °F).
- Wet boiling point: at least 180 °C (356 °F).
- Standards: exceeds SAE J1704, FMVSS 116 DOT 3 and DOT 4, ISO 4925 and JIS K2233.
Castrol describes it as a high-temperature alternative to DOT 5.1 fluids.
How to use it
- Compatible with DOT 3, DOT 4 and DOT 5.1 fluids, but Castrol advises not mixing to keep full performance.
- Change it on the vehicle maker's schedule, or every 2 years if no schedule is given.
- Not for systems that use mineral oil fluid.
Pros and cons
Pros
- Big heat margin over standard DOT 4
- Good corrosion protection
Cons
- Not low viscosity; check what your car needs
- Racing cars may still need SRF
Before you buy brake fluid
- Check your owner's manual or the reservoir cap for the fluid your vehicle needs.
- Never use DOT 5 (silicone) fluid unless your system is designed for it, and never mix it with glycol fluids.
- Only open a new, sealed bottle. Brake fluid absorbs moisture once opened.
- Brake fluid damages paint. Wipe up spills right away.
Safety note: brakes are safety parts. If you are not sure how to do the job, have a qualified mechanic do it.