If you're into doing your own automotive maintenance, or you like to do the odd repair now and then, or even if you watch TV in the winter, you've probably heard of a thing called antifreeze. Then, if you're talking to somebody else, or checking out an article about keeping your car running well in all types of weather, you've heard of something called coolant. The weird thing is, when you read about antifreeze and coolant, it sounds like they serve very similar purposes in the engine of your car or truck. So you ask yourself, what's the difference between coolant and antifreeze anyway? Antifreeze , also called coolant, is the colored fluid (usually green or red) found in your radiator. Antifreeze serves a few purposes. The most important is keeping the water in your radiator and engine from freezing in cold temps. It also keeps that same water from boiling over in the summer. Radiators are normally filled with a 50/50 mixture of antifreeze and water. Th...