Abstract: As of 2022, U.S. Army engine coolant is governed by Commercial Item Description (CID) A-A-52624A, which mandates the use of antiquated conventional, supplemental coolant additive (SCA) based technology. SCA based coolant (hereafter “conventional”) lacks key advantages of the newer more widely used Organic Acid Technology (OAT) based coolant, also known as Extended-Life Coolant (ELC). ELC has been commercially available and used in passenger cars since 1995, with General Motors being the first OEM to adopt OAT technology in their factory fills, but the U.S. Military has not yet adopted the use of OAT technology [1][2]. One disadvantage of conventional coolant is that it has a short life span of two years on the condition that additives are re-inhibited every six months. In 2015, the Ground Vehicle Systems Center (GVSC) learned from the Combined Arms Support Command (CASCOM) that the re-inhibition process was not occurring at field level maintenance, and instead a full flush and refill was conducted annually. This unnecessarily increases the maintenance burden and quantity of coolant being used. This report is in support of the Enhanced Performance Coolants (EPC) task of U.S. Army Combat Capabilities Development Command (DEVCOM) GVSC’s Ground Systems Fluids and Fuels (GSFF) research project. The objective of the EPC task is to evaluate a series of ELCs for use in military ground vehicles and define military-specific fluid requirements to safeguard Army ground vehicle cooling systems in all operational environments.