What Is Antifreeze?

Antifreeze being poured into an oil reservoir in a car
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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. The third function of antifreeze, or coolant is lubrication -- it lubricates the moving parts it comes in contact with, like the water pump.

How Does It Work?

The key chemical component in today's coolants is ethylene glycol. Mixed correctly, this stuff can keep your radiator fluid from freezing even if the temperature is less than 30 degrees below zero! Ethylene glycol can be diluted in a solution of 50 per cent water and 50 per cent coolant (or antifreeze!) to lower the freezing temperature of the fluid in your radiator by 60 genres or more. That's cold. But coolant isn't finished amazing you yet. The even more, or at least equally amazing thing is that it can also keep the same fluid from boiling at as much as 275 degrees Fahrenheit. Considering water alone will reach its boiling point at 212 degrees fahrenheit, that's a pretty noteworthy accomplishment. Antifreeze can really get control of those water molecules!

Maintaining Your Cooling System

Over time, your coolant can become dirty as it picks up gunk that has settled in your cooling system. This buildup can cause clogged subsystems in your cooling system. IN a modern engine, there are lots of fairly narrow passages that the coolant flows through in order to keep your engine cool. Not only is it doing a general job of cooling the engine, these smaller coolant passages keep the heat in the engine balanced as well. When you start your engine in the morning, especially on a cold day, it's important to the engine management system that the engine gets warm as quickly as possible. Today's emission control systems rely on the engine being at its operating temperature for all of the pollution stopping devices to function at their fullest. So not only does your cooling system want to keep the engine from getting too hot, it also wants it to get to its proper operating temp as quickly as it can so that it will stop polluting the air as soon as possible after startup. In a modern vehicle's engine, there are numerous routes that your coolant takes.

Some are large radiator hoses, others are small passages that service things like your heating system or sensors for engine management. There's also the radiator itself, the water pump, and the heater core (your car's way of getting nice hot air on your face in the winter).  All of these are super important.  Flushing your cooling system can keep buildup at bay and keep your coolant flowing freely. Ignoring it for too long can result in lots of gunked up parts, and unnecessary car repairs, and money!