Auto Talk: All about coolant

All car engines have some type of cooling system. Most use a liquid coolant that circulates around the engine to carry heat away. How does coolant work and what do you need to know about it?

Coolant is a mixture of water and various chemicals. The chemicals help prevent rust, neutralize acids and lubricate moving parts such as the water pump. They also increase the boiling point and lower the freezing point of the water. Many people refer to coolant as antifreezeóthis is an outdated term, as protection against freezing is just one of many tasks the coolant handles.

There are four main types of coolant available. Contrary to popular belief, you canít tell them apart by color. Coolant manufacturers can make their products any color they like.

Check your ownerís manual to see if the car came with Dex-Cool originally. If so, stick with it. If not, simply choose a coolant based on price or other factors that are important to you. Standard, recycled and environmentally friendly coolants will all work the same in your vehicle.

For the cooling system to work properly, the coolant must be full, and it must have the correct concentration and pH level. The first is easy to check. The small plastic overflow tank near your carís radiator will have two lines on it. When the engine is cold, the coolant level should be between these two lines. If itís too low, add some coolant, pre-mixed with the amount of water specified on the label.

The concentration and pH level can be estimated with a paper test strip, available at auto parts stores. (A truly accurate test can be done by your auto technician, using a refractometer.) If the pH isnít balanced but the coolant is still good in other ways, adding a bottle of anti-rust will bring things back to normal and extend the life of your coolant.

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