Bosch ESI6 Extended Service Brake Fluid

The Bosch ESI6 is labeled as DOT 4, the specification that requires a minimum dry boiling point of 446°F and a minimum wet boiling point of 311°F per FMVSS 116. In fresh condition, the SDS documents a dry boiling point of 519.8°F — 73.8°F above the DOT 4 threshold, which is in the upper tier for DOT 4 fluids on the market. All brake fluid absorbs moisture over time, lowering its heat resistance; the manufacturer claims a wet boiling point of 365°F — 54°F above the DOT 4 minimum after moisture absorption — though this figure comes from the product listing and has not been published in an independent test document. The product is engineered to simultaneously clear the boiling-point requirements for DOT 3 and DOT 5.1 as well, reflecting chemistry that is more capable than the DOT 4 label alone suggests. ABS, ESC, and traction control compatibility is explicitly confirmed on the product label.

The ESI6 is well suited for daily drivers and light to moderate performance use where DOT 4 is the OEM specification. The documented dry boiling point provides meaningful fade resistance above commodity DOT 4 fluids that cluster near the 446°F threshold, and the brand's OEM-heritage credibility is backed by 4.8 stars across 3,700+ Amazon ratings. Skip if your vehicle explicitly requires DOT 5 — the ESI6 is a glycol-ether fluid and is physically incompatible with DOT 5 silicone systems; the product label marks DOT 5 as an explicit incompatibility. For high-performance or track use requiring a product with a DOT 5.1 label certification and third-party-verified boiling points well above 500°F dry, a dedicated DOT 5.1 performance fluid may be more appropriate.

The SDS signal word is WARNING. H361 classifies this product as a suspected reproductive toxicant (Category 2). SDS §8 specifies safety glasses and chemical-resistant gloves during handling; splash risk during pressure bleeding and overhead caliper work means eye protection is warranted for those operations. No respiratory hazard codes are present at mixture level; standard garage ventilation is adequate for brake service. The sweet taste of brake fluid is a documented attractant for pets and children — store in a sealed, inaccessible location. The product carries a California Prop 65 warning disclosed on the product label and SDS §15. Spent brake fluid cannot be poured down a household drain or storm sewer; collect it during a flush and dispose of it at a used-fluid collection facility.