An organic corrosion inhibitor present as a key component in the additive package of Organic Additive Technology coolants (OAT, carboxylate coolant, extended life coolant.) Carboxylates may also be present in hybrid coolants in combination with inorganic inhibitors. Carboxylate inhibitors provide protection against corrosion for cooling sytem components are often distinguished from inorganic inhibitors in that they deplete or are used up at a very slow rate, thus providing extended life coolant properties