Antifreeze is a chemical which improves the cooling properties of water so that its boiling point is higher and its freezing point is lower. It has a sweet but mildly harsh scent, and is quite toxic. The two most common formulations are ethylene glycol (yellow-green) and propylene glycol (red-orange).
A second chemical feature of antifreeze is its anti-corrosion properties, which prevent components like the radiator and thermostat from getting rusty and clogged up.
What's Different About Dex-Cool?
Different than the standard formulation of antifreeze, Dex-Cool is a longer-life formula designed for GM vehicles with aluminum radiators. It is not mandatory for the qualifying vehicles, but it isn't meant for some vehicles, such as ones with copper radiators. It should also not be mixed with other types of coolant. Dex-Cool is a propylene glycol coolant and is typically an orange-red color.
Many automotive manufacturers prefer to formulate longer life or improved performance antifreeze coolants.
Newer Toyota vehicles are now coming filled with "Toyota Pink" or "Toyota Red". These antifreeze formulations don't have silicates in them like the common basic yellowish-green ethylene glycol. The 50/50 mix contains water, ethylene glycol, diethylene glycol, sebacic acid, and potassium hydroxide. A one gallon bottle of the full strength formula (part number 00272-1LLAC-01) is shown at the right.
Hybrid Organic Acid Technology
HOAT, or Hybrid Organic Acid Technology, is a type of phosphate-free coolant that many European cars and some North American cars have used. It can be found colored golden, blue, or lime green, such as with the Zerex G-05 gallon bottle pictured at the right. The Zerex G-05 formula contains ethylene glycol, water, diethylene glycol, sodium tetraborate, sodium benzoate, corrosion inhibitors, defoamers, and dyes.