Is your vehicle's coolant system ready for summer?

Whether you call it engine coolant or antifreeze, the fluid in your radiator multi-tasks, circulating throughout your engine block and keeping the works running smooth.

What Is Coolant?

Generally, coolant is a half-and-half mixture of a form of glycol and water. The glycol represents the antifreeze element of the mix, guaranteeing that the fluid doesn't turn into ice under harsh winter conditions. Glycol also prevents the coolant from reaching the engine’s boiling point in high summer heat; it keeps engine temperatures stable under all climate extremes and driving conditions.

Coolant/antifreeze also includes additional additives that prevent rust and corrosion in the radiator, engine and the vehicle's heater.

Like any other engine fluid, the coolant needs to be checked on a regular basis. You're checking for two things: quantity and condition. Since the 1970s, most vehicles have a coolant recovery tank or overflow reservoir, which makes checking the fluid level a lot easier and safer. The configuration of the radiator and tank/reservoir lets hot coolant expand into the tank as the engine temperature rises. When the engine cools down, a slight vacuum forms in the radiator and the fluid is drawn out of the tank/reservoir and back into the radiator. As long as the radiator cap remains sealed, the coolant can expand and contract without losing a drop.



Nothing is ever all that simple, though. Some vehicles' recovery tanks are pressurized when the engine is hot, making the caps as dangerous to remove as radiator caps. If your cap is clearly marked with a warning decal leave it to the professionals to check.

In addition to checking for an adequate amount of fluid, you should examine the condition of the fluid. Coolant that's still working looks like clear, slightly thick lemonade, a pale greenish-yellow color. Long-life coolants are orange, like pale orangeade. No matter what the color, the key is that it's not brownish or dirty looking and that flecks of rust aren't floating around in it.

If the coolant is in bad condition, it's time to have the system flushed. The most common service interval for flushing the system is every 30,000 miles. When your vehicle goes longer than that timeframe without fresh fluid, your engine may suffer some damage.


So take care of your coolant—and your engine will stay cool on those long road trips this summer.