For 20 years, this writer lived, toiled and drove cars and pickup trucks smack dab in the middle of the frigid Canadian Great White North. For the uninitiated, normal low, nighttime temperatures in the driest and coldest winter months (January and February) range from -15 to -25°C (translated, that works out to 5 to -13°F), while daytime temperatures range from -5 to -15°C. Winter temperatures can be as low as -30 to -40°C (-22°F to -40°F) and, when the wind is taken into consideration, temperatures feel even colder. The further north you go, the colder it becomes (the record for cold in the Canadian province of Saskatchewan is -70.6°F - and it can get colder in other places).
At a mere 40 below, metal doesn't like to bend or move. It sometimes breaks. Vehicles don't like to start either. That's why it's critical in cold weather climate to always remember to plug the car in, using a 110-volt block heater to keep the coolant toasty while the car is parked. But when you leave your car unattended (and not plugged in), you can be sure of two things: It will refuse to start and/or the coolant might freeze - particularly if your cooling system hasn't been properly serviced. Once the antifreeze/coolant freezes, the engine will quickly overheat, and more parts break. Almost as bad, if the coolant freezes, the vehicle's heating system won't work. That means you freeze.
Because of these simple facts of severe winter life, folks who reside within the deep freeze seldom forget to service the cooling systems of their cars. Most are also quick to check the potency of their coolant (determining at what point it will freeze). Almost all cooling systems are engineered to use a blend of Ethylene Glycol-based antifreeze mixed with good quality soft water. It is designed to prevent summer boil-over and, obviously, winter freeze-up. If one waits too long (in terms of years of use or miles of use) to change their antifreeze/coolant, the used coolant can harm cooling system components and compromise freezing, boiling and corrosion protection.
Choosing the Right Antifreeze/Coolant.
So far so good, but today's coolants (and motor vehicles) are far different from those used in the past. Even more perplexing is the proliferation of new products on the market. That brings up the big question: What products should you use in your cooling system?
Several companies offer specially blended coolant packages engineered so they're universal in nature. That means you can either add a high performance coolant to existing coolant already in your engine and radiator, or flush out the system (the preferred method) and fill it with the good stuff right from the start. Now, the reasons for flushing and changing coolant are many, but the most important is the fact that coolant wears out, much like engine oil.
Does Color Matter?
Isn't the color of coolant important? Not really. You see, color does not necessarily indicate the type of corrosion inhibitor contained within the coolant. You have to read the label. Mixing different types of antifreezes can reduce their corrosion protection and can actually lead to corrosion problems.
But there's a big caveat here: The folks from Prestone have released an Extended Life Antifreeze/Coolant that is compatible with any antifreeze/coolant, regardless of color, in any make or model passenger car or light duty truck on the market today. According to Prestone, this patented formula provides a high degree of performance durability and carefully balanced protection against temperature extremes and rust corrosion of all cooling system metals, including aluminum.
How effective is this new coolant? With a 50-50 mix of coolant and water, the Prestone Extended Life Antifreeze/Coolant is good from -34°F all the way up to 265°F. With a 70-30 mix, the antifreeze/coolant is effective from -84°F to 276°F — sufficient for almost any inhabited locale in North America.
Prestone notes that the best way to insure maximum performance from a premium antifreeze/coolant such as this is to flush the cooling system in your car. Draining the system removes loose sediment and rust from the radiator. If you flush it, the block is cleaned as well (we typically use a system flush/cleaner such as Prestone's Super Flush). Once flushed, fill the system with Extended Life coolant in the mix percentage (50-50 or 70-30) that's applicable for your climate.
As far as the water part of the equation is concerned, good quality soft water will often suffice, although some vehicle manufacturers recommend the use of either de-ionized water or distilled water in conjunction with antifreeze/coolant. In terms of coolant life, this antifreeze/coolant from Prestone is good for five years or 150,000 miles (whichever comes first). This is in part due to the special chemistry found within the coolant's integral corrosion inhibitor package.
When disposing of used coolant, be sure to adhere to local laws and regulations. It's a good idea to dispose of used antifreeze/coolant at facilities capable of handling household hazardous materials. Never discard coolant into storm sewers, septic systems or onto the ground.
So far so good, but how do you know the coolant mix is correct for your climate? Simple. Use a tester. There are plenty of different models out there (hydrometer or refracto-meter). A hydrometer incorporates a float to measure the specific gravity of the antifreeze water mixture, indicating the amount of glycol by way of graduated markings on the gauge body.
In contrast, a refracto-meter measures the bending of light by the coolant/water mixture to determine the amount of glycol in the blend. Inexpensive hydrometers are easy to use - they simply have the minimum temperature capability marked right on the gauge. By the way, it's a good idea to measure the coolant and water mix before you pour it in the engine (radiator).
Mix It Up.
What if you don't want to mix antifreeze/coolant (with water)? For extreme temperatures, mixing will likely prove mandatory. You should never have the need to exceed the 70-30 mix, however. For warmer climates, a 50-50 coolant/water mixture is recommended. But what about a 50-50 pre-mixed antifreeze/coolant solution? These ready-to-use antifreeze/coolants offer freeze-up protection to -34°F and boil-over protection to 265°F. However, since residual water always remains in the system even after a flush, a pre-mix product is recommended only for topping off. The concentrate antifreeze/coolant is best when performing a complete flush.