Coolant: What it Does and Why It's Important

Your car or truck requires periodic maintenance to reduce wear and tear on its components, extend engine life, and to keep it running smoothly. The components of your engine each play an important and vital role in its operation. Let's examine engine coolant including what it's made of, its dual purpose, and the important role it plays in engine operation.

What is Coolant?

Coolant is a mixture of distilled water and alcohol. Also referred to as antifreeze, its primary function is to absorb the extreme heat generated by a running engine. Coolant is introduced to the engine block and its components through a reservoir affixed to the radiator. When the engine is running, the coolant continuously circulates through the engine and back through the radiator. The radiator is affixed to the front of the vehicle, just behind the grill, to maximize air intake. As air passes through the fins on the radiator, it cools the circulating coolant.

Heat Absorption

A man inspecting an overheating car engine

Over half of the energy produced by a fuel burning engine is converted into heat. While some of the heat is expelled through the engine’s exhaust system, plenty remains in the engine block where it will do great harm if left unchecked. That is where the coolant comes into play. As the fluid passes through the engine block, it absorbs the excess heat to help control engine temperature. Without coolant, your engine would reach temperatures beyond its tolerance levels and seize, resulting in a costly engine overhaul.

Freeze Protection

Many folks live in regions of the country subjected to freezing temperatures during the winter months. As its alternate name—antifreeze—suggests, coolant has a dual purpose, it resistance to freezing. For example, if you used plain water as your engines coolant and the temperature dropped below freezing, you could experience severe damage to your engine and its components. This is due to the fact that as water freezes, it expands. The increased pressure from the expansion could crack your engine block, cylinder heads, and other engine components.

Coolant and Electrolysis

As your coolant ages, it can succumb to electrolysis and develop an acidic nature. If you fail to periodically flush the system and change the coolant, it can start to erode your engine and its related components. Refer to the coolant manufacturers suggestions regarding how often you should change the coolant.

Benefits of Engine Coolant

A coolant tank under the hood of a car

The benefits of adding a quality engine coolant to your vehicle far outweigh its costs.

  • Prevents coolant system from freezing during the extreme temperatures of winter
  • Prevents coolant system from reaching boiling temperatures during the summer
  • Helps to reduce engine rust and corrosion in the coolant system
  • Extends the life of rubber and plastic components of the coolant system
  • Helps to reduce electrolysis, which can erode engine components and cause costly repairs

Coolant Maintenance

While you should always refer to manufacturers guidelines regarding how often you should change the coolant, most professionals agree the coolant system should be flushed and changed about every 50,000 miles.

Coolant Warnings

Antifreeze/coolant is extremely poisonous. You should store coolant in a safe and secure place out of the reach of children and pets. Dispose of used antifreeze in an environmentally safe manner. Refer to the manufacturers warning label for safe handling and disposal of unwanted coolant.