Zerex® ZXEL1 - Dex-Cool™ Long Life Concentrated Engine Coolant, 1 Gallon

Today's engines are often nestled in some tight engine compartments under a sleek hood that's low, (the radiator is) pretty obstructed, the front end (of the car) for style reasons could be closed and (there's) not much good air flow. So in modern cars, they would overheat in a matter of minutes if they didn't have an active functional cooling system.

Depending upon the type of vehicle (car or truck), it may require specialized additives that are intended specifically for the needs of the manufacturer's vehicle you have (particularly for imports), or for the type of mileage on your ride.

In order for heat to be effectively transferred, you need a liquid in the cooling system. If coolant freezes, it expands – and with that expansion comes breaking and cracking, which can lead to engine failure and damage.

If coolant boils, the gas/vapor formed does not transfer heat well, so metal could actually melt in the engine if you don't keep liquid in contact with it in some places that need to stay cool. Coolant also protects metals and non-metallic elastomers (rubber parts and plastic parts in the engine and the cooling circuit).

According to Turcotte, "If you were just to use water and not operate the engine at all in the winter, as soon as it cools below freezing, the water will expand about 10 percent on freezing and makes a big old ice cube. That may fracture the cylinder heads, the block, and split open the radiator seams."