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How Chicago Auto Repair Shops Keep Cars Running in Any Weather

BY: Editors | Jul 14, 2015

Ask any Chicago auto-repair shop how to cool your engine in the summer and keep it from freezing in the winter, and they’ll likely give you the same paradoxical answer: antifreeze. Like dunking your engine in Lake Michigan—only without the corrosion or dangerous mineral deposits—antifreeze regulates an engine's temperature in the most extreme conditions, making it almost as essential as gasoline for transportation in Chicago. But how exactly does it work? Below, we answer two key questions about the elixir of car-life.

What is antifreeze?

It’s a modern coolant that lowers the temperature of engines more effectively than tap water, which, surprisingly, was used to douse engines in the old days. Spiked with ingredients to prevent corrosion, antifreeze essentially changes the freezing point of water, and can also keep it from boiling until it reaches about 220 degrees. This allows the engine to safely get hotter than usual. However, the mixture has to be exactly right. If the coolant becomes too diluted, the freezing point starts to creep back up.

What’s the best antifreeze formula?

We’re still figuring that out. So far, almost all formulas use some kind of alcohol, whose freezing point is around 206 degrees lower than water's. Early antifreeze used methanol, but its low boiling point made it ultimately impractical, so most formulas today are based on propylene glycol or ethylene glycol. Though cheaper to produce, the latter comes with a greater cost: it's extremely toxic, a danger exacerbated by its sweet, syrupy taste. Some manufacturers have helped protect children and pets by adding a bittering agent to the formula, giving it the same foul taste of broccoli found in other poisons.