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Prices may varyThis product ranks #15 of 16 in Coolant / Antifreeze.Three above it ↓
Last reviewed June 9, 2026
TL;DR Meets ASTM D3306 and D4340 with an OAT (organic acid technology) inhibitor package, phosphate-free and silicate-free, but carries no named OEM approval numbers. Ethylene glycol base: the H302 (harmful if swallowed, Cat 4) classification applies; keep this coolant secured from pets and children, or choose a propylene glycol alternative.
Peak Long Life is a pre-diluted 50/50 OAT coolant meeting ASTM D3306 and D4340, the baseline performance specs for passenger car cooling systems. The OAT inhibitor package supports a manufacturer-stated 5-year/150,000-mile drain interval; community VOA data confirming the 150k-mile mark is limited on BITOG as of 2026. Ethylene glycol base (90-97% by weight); the pre-diluted formula adds deionized water and a denatonium benzoate bittering agent. Available on Amazon in 2-pack or 6-pack only; single gallons are sold in-store at Walmart, AutoZone, and O'Reilly.
Best for owners of older or less-restrictive vehicles (pre-2010 domestic or Asian-brand cars) needing a budget OAT coolant for a basic flush and fill without paying for an OEM-specific formula. Skip this if your vehicle's owner's manual specifies a named OEM coolant (GM DEXOS, Ford WSS-M97B44-D, VW TL 774-G, Toyota SLLC); Peak Long Life carries no published OEM document endorsements and the wrong inhibitor package can cause corrosion in OEM-specific systems. Also skip if you need a propylene glycol formula for a pet- or child-safety reason.
Signal word: WARNING. The primary hazard is H302 (harmful if swallowed, Cat 4) from the ethylene glycol base at 90-97% by weight; the product also carries a California Proposition 65 warning for ethylene glycol (developmental toxicity). The denatonium benzoate bittering agent at 30-50 ppm meaningfully reduces palatability but does not change the H302 classification. SDS §8 specifies gloves where skin contact is possible (H315) and eye protection for splash risk (H319); no inhalation H-codes are present and SDS §8 specifies no respiratory protection for normal pour-fill at ambient temperature. Collect spent coolant for recycling at auto parts stores; do not drain to ground or storm sewer.
Peak markets Long Life as compatible with 'all makes and models.' No named OEM spec document numbers (GM DEXOS, Ford WSS-M97B44-D, Toyota SLLC, VW TL 774-G, etc.) were found on the label, the product listing, or in any available technical data sheet as of May 2026. Owners of vehicles with strict OEM coolant specifications, particularly European vehicles (VW, BMW, Mercedes) or newer Asian OEM systems, should verify the correct specification from their owner's manual before using a generic OAT formula.
Ethylene glycol (EG). The SDS (Section 3) lists ethylene glycol at 90-97% by weight. Ethylene glycol is acutely toxic if swallowed; the H302 classification (harmful if swallowed, Cat 4) applies, and the product carries a California Proposition 65 warning for ethylene glycol (developmental toxicity). If you need a less-toxic alternative for a household with pets or children, propylene glycol-based coolants are materially safer on this axis.
Denatonium benzoate is a bittering agent added at 30-50 ppm to deter accidental ingestion by pets and children. Ethylene glycol has a mildly sweet taste that can attract animals; denatonium benzoate is one of the most bitter compounds known. Its presence is disclosed on the product listing feature bullets ('Product contains bittering agent - denatonium benzoate'). This additive meaningfully reduces palatability but does not alter the H302 toxicity classification; the product is still harmful if swallowed.
Peak claims 5 years / 150,000 miles when a complete cooling system flush and fill is performed (not top-off use). The 5-year portion of this claim is consistent with OAT inhibitor chemistry, which degrades more slowly than silicate-based (IAT) coolants. Independent used-coolant analysis (VOA) data specifically corroborating the 150,000-mile portion of the claim is limited in public community forums (BITOG) as of 2026. Standard guidance: test your coolant's pH and inhibitor reserve at 3-year intervals rather than relying solely on the label claim.
No. Ethylene glycol coolant, used or fresh, must be collected and brought to a recycling program. Most auto parts stores (AutoZone, O'Reilly Auto Parts, Advance Auto Parts) accept used coolant at no charge. Storm drain or ground disposal is prohibited under the Clean Water Act in most US jurisdictions and causes documented harm to aquatic environments and wildlife. The sweet smell of EG also attracts animals, increasing the risk of ingestion if spilled or left in open containers.
Marketing copy from PEAK, via Amazon. Not editorial.
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