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Prices may varyThis product ranks #8 of 14 in Coolant / Antifreeze.Three above it ↓
Last reviewed June 4, 2026
TL;DR GM's OEM DEX-COOL concentrate -- meets ASTM D3306 and D4985; OAT inhibitor package (silicate-free, phosphate-free) with a 5-year/150,000-mile drain interval on the label. Ethylene glycol base with a Prop 65 reproductive harm warning -- keep away from pets and children.
ACDelco DEX-COOL (12346290) is GM's OAT extended-life coolant concentrate. The organic acid inhibitor package is silicate-free and phosphate-free -- the spec for GM vehicles that left the factory with DEX-COOL. Protection range is -34F freeze to +265F boil at 50/50 per the back label. The 5-year/150,000-mile drain claim is consistent with OAT chemistry, though no independent used-coolant analysis exists to confirm it in field conditions. Ethylene glycol base -- an ingestion hazard; store away from pets and children.
Best for GM vehicle owners (Chevy, GMC, Buick, Cadillac) whose manual specifies DEX-COOL. Skip for European vehicles requiring Si-OAT (VW/BMW) or Asian vehicles with their own OAT specs. Buyers wanting lower household toxicity should consider a propylene glycol coolant.
SDS signal word is WARNING. Ethylene glycol base carries an ingestion hazard (H302, harmful if swallowed) and a suspected reproductive toxin classification (H361); Prop 65 reproductive harm warning is on the back label. SDS §8 covers gloves and eye protection for drain and pour contact; H373 (STOT RE Cat 2, kidneys) reflects a repeated-exposure organ classification. Collect spent coolant for recycling at an auto parts store -- do not drain to the ground or storm sewer.
Yes. ACDelco is GM's own OEM parts brand. Part number 12346290 is the genuine GM DEX-COOL concentrate -- the same fluid used in GM dealership coolant services. Manufactured by Prestone Products Corporation for General Motors.
Yes. The product label and the product listing confirm a bittering agent is included (typically denatonium benzoate at trace concentrations). This makes the coolant taste unpleasant to deter accidental ingestion -- but it does not eliminate the toxicity. Ethylene glycol is harmful if swallowed and carries a Prop 65 reproductive harm warning. Keep secured from pets and children.
DEX-COOL is GM's OAT coolant specification covering GM passenger cars and light trucks that specify DEX-COOL in the owner's manual. The label confirms ASTM D3306 (automotive) and D4985 (heavy-duty diesel). Do not use in vehicles requiring a different spec (e.g., European Si-OAT or Asian OAT formulations) without confirming compatibility.
The label states 5 years or 150,000 miles. No independent used-coolant analysis for this specific ACDelco-branded SKU exists to confirm that interval in field conditions. The OAT inhibitor chemistry (carboxylate-based, silicate-free) is consistent with extended-life claims.
The back label carries a Prop 65 reproductive harm warning. Ethylene glycol (CAS 107-21-1) is on the California Prop 65 list for reproductive toxicity. The SDS also carries an H361 classification (suspected of damaging the unborn child, Cat 2). The SDS §15 states no Prop 65 warning is required for consumer packages -- the back label is authoritative.
Marketing copy from ACDelco, via Amazon. Not editorial.
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