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What’s Up With That? How Antifreeze Works.

It’s like salt on an icy road but inside your engine

When you start your car up in the dead of winter, a cascade of mechanical functions spring to life. The combined forces of those functions produce a tremendous amount of heat – up to 2800 degrees Fahrenheit (F) inside the pistons. So wait, with all of that heat, why would you need a thing called “antifreeze”?

Well, that stuff we call antifreeze actually works to protect the fluid that keeps your engine cool enough to not self-destruct (you’ll also hear it called “coolant”). Constantly circulating around your engine chamber, it carries enough of the heat generated by all of that firing and turning to the radiator, where it is cooled by outside air. Some of that heat is also used to heat the air that makes the interior of your vehicle cozy and comfortable. 

The earliest car engines just used water to cool their chambers, but plain old H20 turned out to be not very efficient and also the cause of many headaches come wintertime. Just like an unprotected pipe on a cold winter night, if your radiator is filled with just water, it will freeze and might burst. Then, when you start your engine you won’t get any cooling effect until the water thaws, and you certainly won’t get any after it sprays out of the newly formed split in your radiator.  

The answer? Antifreeze. Despite its one-sided name, this essential fluid does more than just protect your car from winter’s icy grasp. It also prevents your radiator from boiling over in the dog days of summer, thanks to its ability to both lower the freezing temperature of water and raise its boiling point.

Icy Roads and Vehicle Engines: More Similar Than You Might Think

In its natural state, water freezes at 32 F and boils at 212 F. When we salt a road before a snow or ice storm, the salt and water bond, creating a new liquid (salt water) with a freezing point about 20 F lower than pure water (in the original Fahrenheit scale, 0 was the freezing point of sea water, 32 the freezing point of fresh water, but that was changed for some reason we don’t have time to get into here). So, when the winter storm comes in, and the snow or freezing rain hits the road, the water and salt bond, and the liquid salt water runs safely off. Unlike roads, though, your engine can’t survive regular doses of salt water. It would quickly rust away like exposed metal by the seaside. 

Enter ethylene glycol. Like salt, it bonds with water to form new liquid. Better than salt, this new liquid won’t freeze until the temperature drops to 30 F below zero (62 F lower than water), and won’t boil before it gets to 275 F.  Plus, it won’t damage your engine. Plus, plus, it acts as a lubricant to extend the life of your vehicle’s water pump. 

Keeping Your Engine in the “Goldilocks Zone”

In warmer weather or on extended drives, your engine can get hot enough to evaporate small portions of your antifreeze. Over time, these small evaporations can add up to too little coolant bathing your engine, followed by overheating, followed by a twisted, steaming mass of metal under your hood where your engine used to be.

To keep your engine just right – not-too-hot and not-too-cold – we check your antifreeze every time you come in for an oil change – or any other service. If it needs a little boost, we’ll be happy to top it off. And since, like anything that heats and cools and heats and cools, day after day, antifreeze wears out, we recommend a full coolant flush about every 3-5 years.

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