Put down the wrench (or the smart phone, more than likely) for a second and think about just how far the automobile has come in recent decades.

Cars can now parallel park themselves; use infrared to see in the dark; magnetize fluid to change how they ride; and communicate with satellites to bring you music, directions, or a Mexican restaurant recommendation.

Now consider that despite all that there’s still some basic tech at play in your vehicle that was around when your dad bought his first car. Stuff like oil, air filters and our subject here: antifreeze.

If you break down exactly how your engine makes power you’ll realize you’re essentially moving along thanks to a series of tiny explosions — hence the term “internal combustion.”

As you’d expect though, this, along with friction for all those moving parts, produces heat and expansion. A lot of it.

Keeping cool under your hood, then, is key to a long, healthy life for your engine. There’s a specific temperature at which your motor’s designed to operate, no matter the season. This is where liquid antifreeze, or coolant, comes in.

Your motor essentially has a pressurized, closed loop circulatory system. Antifreeze is constantly moved through your engine, absorbing excess heat. It’s then piped to the front of your car, where it passes through a radiator. Fresh outside air and forced air from a fan cool that radiator and the antifreeze inside, before it’s pumped back into the engine and the process starts all over again.


Years ago, antifreeze was simply water. “In the old days [the 1950s] coolant was plain simple water,” says David Redinger, Autofocus’s expert in-house mechanic. “We drained the coolant in the winter and added an alcohol-based coolant, which didn’t freeze.

“Alcohol does not do well in the summer heat, though, as it boils off. So we would switch back to water in the spring.”

Thing are much different today. Water’s actually still used in your cooling system, but the antifreeze you add to it is a chemical compound made mostly of ethylene glycol.

The latter’s actually an organic compound that lowers the freezing point of that H2O considerably and raises its boiling point. Consider the wild temperature extremes we see in Canada and you’ll understand why this is necessary.

So how come BMW’s antifreeze is blue and GM’s is red? Because today’s carmakers all build their engines to different specifications, and from different kinds of metals. What the motor’s made from determines what kind of rust and corrosion inhibitors – or silicates for aluminum protection – go into the antifreeze formula.

“Some European car manufacturers recommend that phosphate-free antifreeze be used in their vehicles,” note some of the experts at Peak Antifreeze.

“The reason is that the water in Europe has an extremely high mineral content. If you mixed an antifreeze containing phosphates, which are part of the corrosion inhibitor package, with the water they have in Europe, the phosphates in the antifreeze may ‘drop out’ and form deposits in your cooling system that can lead to corrosion. However, this is not a major concern in North America, since our water is lower in mineral content, or softer, than European water.”
There are a number of aftermarket producers (Peak, Prestone, MotoMaster, for example) that make antifreeze that’s up-to-snuff with the car manufacturer’s recommendations. Read your owner’s manual or consult your local service centre to find out which is right for your car.

Do you have to change your antifreeze? Yes; again, consult your owner’s manual or your local service centre for this info.

The good news is that the antifreeze in a vehicle put through normal use has a pretty long life cycle. GM, for instance, says a 2005 Chevy Cavalier should be able to last some five years, or 240,000 km, before its first antifreeze flush.

“Flush and refill every five years and you’re good to go,” Redinger agrees. “Why? The antifreeze mixture contains lubricants, anti-foam agents and other fancy stuff. These chemicals get used up.

“Plus, as antifreeze wears, grit starts to float around the inside of the cooling system. Not only do particles accelerate the wear of the water pump [which moves the antifreeze through your engine], they can actually short or distort your car’s sensor readings.”

If your car has a temperature gauge and it swings way high (or way low) you know there’s an issue with your cooling system.

If your car’s running fine today, note where the needle’s sitting under normal operation for future reference. More and more modern cars, though, don’t have temperature gauges, so watch for a warning light like “low coolant,” or simply the ubiquitous “check engine.”

If you smell something like maple syrup or burnt sugar inside your car, that’s the ethylene glycol, and a warning sign that somewhere there’s a coolant leak. Get the car inspected immediately.

Also note: that syrup or sugary smell from antifreeze makes it enticing to taste for kids and pets. Ethylene glycol is highly toxic stuff, though. Considering Peak says coolant bottles have a shelf life “of many years,” store them safely and high up always.


This is going to depend on how mechanically inclined you are, really. It’s not quite as simple as an oil change. There are guides online for how the whole process of draining and refilling your system is done, like this one from the people at Peak.

Taking your car to a service centre, though, should mean the job’s done right: the old antifreeze is disposed of in an environmentally friendly manner and the trained technicians can inspect the spent fluid for warning signs there’re other issues inside your engine.

Key here is adding back in the right combination of antifreeze (available at an quality automotive supply store) and water. Says Peak, “The optimum coolant combination is a 50-50 mixture… it will produce freeze protection down to -36°C (-34°F) and boil-over protection up 129°C (265°F). However, in colder climates, where lower temperature freeze protection is needed, a mixture of up to 70 percent antifreeze can be used.

Although regular water will do, the refilling of the system should be done with distilled water. Distilled water doesn’t contain any minerals [or chlorine] which can dissolve and cause scale and deposits in your cooling system.”

Always be sure to follow the antifreeze manufacturer’s instructions for the mixture ratios to match your climate.