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Antifreeze/Engine coolant: You know it’s important for your vehicle, but how educated are you on what exactly it is?

What its job is?

Well, we’re here to give you the low down on everything you need to know about engine coolant, from what it is, to what it does, and important things to consider, especially since we’re starting to look ahead to winter when it’s probably time to think about changing your coolants as the temperature drops.


An engine coolant is simply a mixture of antifreeze and coolant, deionized water, corrosion inhibitors, and dyes. Having the right mixture is essential because it prevents corrosion of the cooling system components, and it raises the boiling point and lowers the freezing point. This fluid is magic because not only can it protect vehicles in the frigid temperatures of winter, but it can also keeps cars cool in the blistering heat of summer.

What’s in this powerful fluid?

Most engine coolants have ethylene glycol (EC). EC smells sweet; however, it is a chemical that is both poisonous to humans and animals. Engine coolant also uses propylene glycol (PG), which is less hazardous; however, still quite toxic. Now you know just how powerful this formula is, so the next step is to share how it works.

The propylene glycol and ethylene glycol raise the boiling point of coolant and lower the freezing point. However, water is included to dilute the engine coolant because the glycol fluid doesn’t get rid of heat effectively on its own. Engine coolant often comes premixed because the half water, half coolant mixture is recommended. This mixture should be changed periodically because the corrosion inhibitors will break down little by little.

There are 3 basic coolant technologies, which are:

  • IAT – Inorganic Acid Technology – Green – Mainly only used on older vehicles.
    Lifespan is 2 years.
  • OAT – Organic Acid Technology – Mostly red and orange, but can be pink, blue, or green – Used today because it offers silicate-free protection of all metals and for longer – Lifespan of 5 years or 150,000 miles.
  • HOAT – Hybrid Organic Acid Technology – Usually orange or yellow – Used today – Mixture of IAT and OAT – Orange contains 10% recycled coolant.

Changing antifreeze/coolants

You should check coolant levels every time you go for an oil change. Although trucks can run on the same coolant for hundreds of miles, there are factors that could change that. And as the seasons change, it’s important you have the correct coolant to battle the elements. Make sure your antifreeze/engine coolant is able to protect your heavy duty engine to the lowest temperature you’ll face this winter. And while that may be a seasonal concern, is also very important with regard to engine corrosion, which is a daily concern. Without the right amount of glycol in your coolant, engine corrosion could become a major concern.

Essentially, your antifreeze/coolant should protect to the lowest temperature; protect against corrosion for a wide array of temperatures; maintain engine temperatures for fuel/lubrication efficiencies; and increase the cooling index to prevent over-heating.

Because of all these factors, it’s important you or your mechanic don’t just grab the cheapest bottle of engine coolant you come across. Make sure it’s the ideal one to protect your heavy duty engine against all the elements.

The best way to make sure your engine is using the right antifreeze/coolants this winter and in all seasons is to check with the trained and certified maintenance staff at North Dixie Truck and Trailer. Call us at 419-221-3750 to make an appointment, ask a question or stop by and see us today at 2050 North Dixie Highway in Lima.


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