Antifreeze: A mixture of glycol and water (typically 50:50) with a corrosion inhibitor package. An appropriate mixture balances the need for maximum heat transfer with appropriate freeze protection cold environments.
Azole: These chemicals provide copper and brass protection. The two most common are MBT (Mercaptobenzothiazole) and TTZ (Tolyltriazole).
Borate: A very soluble pH buffer used in premium antifreezes.
Coolant: Fluid used to transfer waste heat away from the engine. Coolant concentrate mixed with water, or water mixed with an additive package for use in warm climates.
Coolant Concentrate: Pure glycol (typically 95%) with an inhibitor package added. Coolant concentrate cannot be used by itself, it must be mixed with water before being put into the engine’s cooling system.
Conventional Coolant: Ethylene glycol that contains a corrosion inhibition package consisting of inorganic inhibitors such as silicate, phosphate, nitrate, and azoles.
Fully Formulated Antifreeze or Coolant: A modern product that contains all of the necessary
inhibitors for both diesel and gasoline powered engines. (TMC RP-329 or TMC RP-330 specifications)
Ethylene Glycol: The most common freeze protection chemical used in the manufacturing of antifreeze.
Nitrite: The primary inhibitor for wet sleeve liner pitting protection. It also protects against rust.
Nitrate: A corrosion inhibitor that protects several metals including iron and aluminum protection.
pH: A scale to tell if coolant is acidic, neutral or basic. Acid is corrosive, neutral or mildly basic is protective.
Reserve Alkalinity: A measurement of the acid neutralizing capacity of coolant.
Silicate: The primary conventional inhibitor for aluminum. In heavy duty coolants, lower (less than 250 ppm) silicate concentrations are generally preferred.
Phosphate: An inexpensive pH buffer. Phosphate is used in some antifreeze brands. It is not permitted in coolant used to protect Mercedes, BMW, Volkswagen MTU or Detroit Diesel engines.
Propylene Glycol: A less toxic, but more costly, alternative to Ethylene Glycol.