Dex Col® (GM Dexcool brand)
Dex-Cool® GM's Extended Life, Carboxylate Inhibited Engine Coolant
Since then, the product has been attacked at every opportunity by competitors who stand to benefit from its failure. Unfortunately, application of the technology in the American market has exposed it to some negative experiences.
Overall, GM is pleased with their decision and intends to continue to use Dex-Cool for the foreseeable future.
GM recommends and represents that Dex-Cool can serve for up to 5 years or 150,000 miles, whichever comes first. To benefit from this service interval, it is important to maintain the cooling system only with carboxylate technologies similar to Dex-Cool.
In addition to the GM brand, Texaco Havoline, Prestone Extended Life5/150, Zerex Extreme Life and Cel-Cool should be very compatible. Dex-Cool contains a mixture of ethylene glycol inhibited with 2-ethyl hexanoic acid, sebacic acid and tolyltriazole. It contains no benzoate, nitrite, nitrate, silicate, or phosphate. The products above are very similar and consistent with that approach.
The best documented negative issue involves light trucks with 4.3 liter engines that have developed brown coolant from corrosion. A technical service bulletin was published to GM dealers regarding this problem. Someone transcribed it to the web, and the transcription can be read at:
http://forums.vmag.com/suvsuburban0402/messages/1665.html
In general, used as directed this is a capable technology.
he key to this, and other new extended life formulations is proper maintenance. That means keeping the coolant system correctly filled and using the same or very similar and compatible products.