What Are Freeze Plugs?

by Lacy Nichols
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Freeze plugs, also known as core or frost plugs, prevent coolant from leaking from your car. Freeze plugs are very important when it comes to the maintenance of a car, especially in warmer climates. Without coolant, your car's engine can reach unstable conditions, causing a breakdown.

History of Freeze Plugs

Many years ago, people would use plain water as opposed to coolant or antifreeze during warmer months. However, many people would forget to replace the plain water, resulting in frozen water inside the engine. The pressure of the frozen water would cause the plugs to pop, resulting in the name "freeze plugs."

How It Works

When the engine block is formed, sand is used to form the basic shape and passageways. The engine block is then combined with iron and aluminum. After cooling, the sand loosens and is removed through holes. These are the same holes that need plugging with the freeze plug.

Changing the Plugs

On rare occasions, freeze plugs will need to be replaced, but they usually last as long as the engine. If for some reason a freeze plug needs replacing, the process is usually fairly simple and can be done by any mechanic. This process can be more difficult based on location.

Changing Antifreeze and Coolants

To keep from having to replace the freeze plugs, simply maintain the cooling system of your car. Antifreeze has certain properties that can cause freeze plugs to rust. To avoid this, change your antifreeze every three years. If antifreeze isn't changed, or if you use plain water, the freeze plugs will rust until the coolant falls out and the plugs need to be removed.

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