AC DELCO DE X-COOL ® Extended Life Antifreeze/Coolant. They can retain 95% concentration after 150 000 miles of the mileage. It helps extend the coolant change intervals and not worry about the loss of protection against corrosion. Application: AC DELCO DE X-COOL ® Extended Life Antifreeze/Coolant is recommended for use in cooling systems of all types of GM automotive engines. AC DELCO DE X-COOL ® Extended Life Antifreeze/Coolant meets ASTM D 3306 for car service maintenance, ASTM D 4985 for service maintenance of machines operating in severe conditions.