Cars Simplified: Everything Automotive Explained

Antifreeze & Coolant

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 typically 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.

Where To Pour Antifreeze/Coolant

Coolant can be poured into the radiator or coolant tank, but it needs to be added in the proper amount and only when the engine is completely cooled down. When hot, the cooling system is under a lot of pressure, and can blast hot coolant out if the radiator cap or expansion tank cap if opened.

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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, as in a best-case scenario, the life span of the resulting mix will be reduced. Dex-Cool is an ethylene glycol coolant and is typically an orange-red color.

The Story of Dex-Cool Video by Cars Simplified

Other Coolants

Many automotive manufacturers prefer to formulate longer life or improved performance antifreeze coolants.

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. That particular Zerex G-05 formula contains ethylene glycol, water, diethylene glycol, sodium tetraborate, sodium benzoate, corrosion inhibitors, defoamers, and dyes.

Toyota Red/Pink

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. This particular 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, in the red and black bottle that reads "Toyota Long Life Antifreeze Coolant".