First: The role of adding a defoaming agent to the antifreeze: Since the car engine will inevitably vibrate during operation, air will enter the antifreeze and produce a certain amount of foam. This affects the transfer of heat. Adding an appropriate amount of defoaming agent to the antifreeze will have a defoaming effect when the concentration of the defoaming agent reaches a certain amount. Defoaming agents mainly use alkyl nonionic surfactants, generally useful glyceryl ether, alcohols, silicones, etc. Second: The effect of adding non-toxic water-soluble colorants to antifreeze: adding non-toxic water-soluble colorants, the (mass) concentration of the colorants is generally in the range of 0.01 to 0.05. The difference from cooling water is to check whether the antifreeze in the cooling system is leaking. It also has the function of a reagent to facilitate observation of the pH changes of the antifreeze. Generally, methyl red, phenol red, methyl blue, etc. are commonly used to allow anti-animal agents to have a certain indicating effect. If the observed color does not match the indicated color, it means that the antifreeze has become acidic, and acidity will not provide antifreeze and antirust effects. Third: The role of adding bactericidal and antifungal agents to antifreeze: Since antifreeze tends to produce microorganisms during storage, in order to inhibit the growth of microorganisms and prevent the antifreeze from becoming moldy and deteriorating, a small amount of bactericidal and antifungal agents need to be added. This ensures that the antifreeze will not become moldy during the storage period of 2-3 years. One of the better ones is sodium benzoate. Fourth: The role of adding corrosion inhibitors to antifreeze: Since the pH value of antifreeze will drop during the working process and the medium will become acidic, adding corrosion inhibitors can control the pH value within a certain range. Commonly used pH regulators include organic Amines, phosphates and phosphates, etc. Fifth: The main quality standards and evaluation methods of antifreeze: The main indicators stipulated in the antifreeze standard include the density, solubility, corrosiveness of water pump cavitation, foaming, (PH value) acidity value, boiling point, and antifreeze (freezing point), discoloration, reserve alkalinity, metal corrosion, etc.