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Prices may varyAbout this product's hazards. This product's Safety Data Sheet uses signal word danger. Read the manufacturer's SDS and follow all safety instructions before use. CarCareTruth ratings translate SDS data — they do not replace the SDS or substitute for a hazard assessment specific to your task.
CarCareTruth's Analysis
Last reviewed May 19, 2026
TL;DR A single-rated DOT 3 fluid that meets the FMVSS 116 dry floor (401°F) but publishes no wet boiling point — the 460°F Amazon spec figure has no TDS behind it. DANGER signal word from serious eye-damage chemistry, with a California Prop 65 reproductive-toxicity warning (H361) on the label.
What it is and how it performs
Prestone AS400 is a DOT 3 brake fluid under FMVSS 116, which sets the federal minimum at 401°F dry and 284°F wet. The SDS confirms boiling point above 401°F — the minimum itself, not a margin above it. The Amazon spec field cites 460°F, but no TDS or third-party test backs that number. The wet boiling point — the figure that actually governs heat resistance after a year or two of moisture absorption — is not disclosed anywhere. For a DOT 3 daily driver the spec is met; there is no objective basis to claim better fade resistance than any other DOT 3 commodity.
Who should buy this — and who should skip it
Best for stock daily drivers where the owner's manual specifies DOT 3 and the goal is a routine fluid change at a common-brand price point. Skip it for any vehicle that specifies DOT 4 — DOT 3 boiling points are lower across the board. Skip it for track use, autocross, or towing in hilly terrain — those use cases warrant DOT 5.1 with documented dry boiling points well above 600°F.
Safety and environmental impact
DANGER signal word from H318 — the most severe eye-damage classification; a splash can cause permanent corneal injury. Wear splash-proof goggles during caliper bleeding; PVC gloves during a full flush. SDS §8 affirmatively states no respiratory protection is needed under normal use. H361 (suspected reproductive toxin) and H373 (kidney damage from prolonged exposure) drive the California Prop 65 warning in §15 — pregnant individuals should be especially careful with handling. The sweet taste of brake fluid is a documented attractant for pets and small children — store sealed and inaccessible, and never decant into an unlabeled container. Used fluid is drain-destined: collect for hazardous-waste disposal, never pour down a drain or storm sewer.
Frequently asked questions
Can I use Prestone AS400 in a vehicle that specifies DOT 4?▾
No. AS400 is rated DOT 3 only — not dual-rated DOT 3 and DOT 4. If your owner's manual specifies DOT 4, the DOT 4 fluid offers a higher minimum dry and wet boiling point (446°F dry / 311°F wet versus 401°F / 284°F for DOT 3). Using a DOT 3 in a DOT 4 system reduces heat resistance below what the OEM specified. Buy a DOT 4 fluid instead.
Is this compatible with ABS systems?▾
Yes. The Amazon listing explicitly states the fluid is 'safe to use in all DOT 3 braking systems (ABS, disc, and drum).' All glycol-ether-based brake fluids (DOT 3, DOT 4, DOT 5.1) work with ABS and electronic stability control. The incompatible chemistry is DOT 5 silicone-based fluid, which this product is not.
What does the Prop 65 warning mean?▾
The SDS Section 15 states this product contains chemicals known to the State of California to cause reproductive toxicity. The classification ties back to the H361 hazard code in Section 2 (suspected of damaging the unborn child). The product is legally sold in all 50 states; Prop 65 is a California-specific disclosure regime, not a ban. Pregnant individuals and anyone handling the fluid regularly should follow the gloves-and-goggles guidance in SDS Section 8.
What is the wet boiling point of this fluid?▾
Prestone does not publish a wet boiling point for this product. The SDS Section 9 reports only that the boiling point is greater than 401°F — that is the FMVSS 116 dry minimum for DOT 3 and is not a separate wet measurement. For DOT 3 the federal wet boiling point minimum is 284°F. Without a published wet figure or a third-party test sheet, the operationally relevant heat resistance after moisture absorption can't be confirmed for this product.
How often should I change brake fluid?▾
Most manufacturers recommend every 2–3 years or 30,000–45,000 miles regardless of how the fluid looks. Glycol-ether brake fluids absorb moisture from the air over time, which lowers the wet boiling point and reduces fade resistance. A brake fluid test strip from any auto parts store gives a more reliable answer than mileage alone.
From the manufacturer
Marketing copy from Prestone, via Amazon. Not editorial.
- •50,000 mile fluid life
- •Prevent overheating & brake fade with high grade formula
- •Protects against performance decline due to water absorption; prevents corrosion of all metals within the braking system
- •Synthetic, extended fluid life formula
- •Size: 12 oz.
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Manufacturer specifications
- Material
- Plastic
- Brand
- Prestone
- Package Information
- Bottle
- Liquid Volume
- 12 Fluid Ounces
- Item Weight
- 12 Ounces
- Brand Name
- Prestone
- Recommended Uses For Product
- Automotive
- Specific Uses For Product
- Prevent overheating, brake fading
- Item Form
- Liquid
- Global Trade Identification Number
- 00797496876423
- Manufacturer
- Prestone
- Unit Count
- 12.0 Fluid Ounces
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