Antifreeze Overview

Seems like just yesterday, when you were flushing your radiator all you needed was to stop by the auto parts store and pick a gallon or two of Prestone antifreeze, which happened to be green in color.

Antifreeze has several tasks that are required under different conditions.

  • Protect the water from freezing
  • Protect the metal parts in the system
  • Lubricate the water pump and seals
  • Raise the temperature that the water will boil over

Well today you have a few more choices to make. Not only can you still get antifreeze in green but you can also get it, red, blue, orange, yellow and gold.

Because the primary ingredient in antifreeze is colorless they have added a dye to it so you can identify it from regular water. The antifreeze manufactures use the different colors to identify different specifications designed for different uses.

In Europe the water is generally very hard with high concentrations of minerals. European car manufactures prefer coolants with little or no phosphates. The phosphates can react with the magnesium and calcium salts in hard water, which can form solids. These solids can wear erode seals or clog narrow cooling passages.

Japanese manufacturers prefer coolants that are free of silicates, but higher in phosphates. It's difficult for the owner of a Japanese import to find this kind of antifreeze at the local parts store or even the dealership. However, for years American shops have been installing the traditional green coolant in Japanese imports with no problems.

American and Japanese coolants contain phosphates to protect the iron and steel parts in the engine. Even though the U.S. has hard water, it is not nearly as hard as the tap water found in Europe. In Europe it is not a good idea to use the standard green coolant. In addition to phosphates, most domestic coolants contain silicone and silicates. The silicone helps lubricate the water pump while the silicates help protect aluminum parts by coating the surfaces.

Basically the different colors represent different metal protection packages. Just FYI on what the different colors are for.

  • Green For American cars
  • Green Dark, some Japanese cars
  • Orange Dex-Cool organic-acid technology (OAT)
  • Yellow DaimlerChrysler vehicles and some Fords specifie a yellow antifreeze/coolant with OAT and silicates
  • Gold DaimlerChrysler vehicles
  • Red Toyota with OAT and phosphates but not silicates
  • Pink Volkswagen and Audi with OAT and silicates
  • Green, Yellow or Blue for European cars

Note: This is just an outline and the manufactures of the antifreeze or the automobile can change this at anytime, please go by what is your owners' manual.

This newest antifreeze/coolant is based on organic acid technology that causes the metals to form a protective layer on themselves.

Note: Ethylene glycol, which makes up 96 percent of the antifreeze/coolant, has about half the heat transfer capability of plain water. So when you mix antifreeze and water in the recommended 50-50 mix, you give up 25% of your system's cooling capacity. Not a problem for newer cars because they are engineered with this mind.

Note: Many people opt to use distilled water instead of tap water, its your choice, today's coolants are designed to work with US hard tap water.

Note: Some people have reasoned that straight antifreeze would provide them with more cold wather protection but actually straight antifreeze will freeze around 8 degrees.

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