The Basics of Antifreeze and Why Your Car Needs It

What Is Antifreeze?

Coolant_TankAntifreeze is the colored liquid found in your radiator. Antifreeze can also be called coolant and can come in a variety of different colors. It serves a few different purposes:
• Antifreeze keeps the water in your radiator and engine from freezing in cold temperatures.
• Antifreeze also keeps that same water from boiling over in hot temperatures.
• Antifreeze also serves as a lubricant for the moving parts it comes in contact with, such as the water pump.

The main ingredient in the coolant used today is ethylene glycol. If it is mixed correctly (a 50/50 mix of antifreeze and water is ideal), the ethylene glycol can keep your radiator fluid from freezing even in temperatures reaching as low as 30 degrees below zero and also keep those fluids from boiling in temperatures reaching as high as 275 degrees Fahrenheit.

You want to make sure that your vehicle has the proper amount of antifreeze at all times. Having a low amount of antifreeze can cause your engine to overheat or freeze up, costing you big bucks in the long run, so make sure to check these levels every 2 to 3 months.

How To Check Antifreeze Levels?

Coolant_LevelYou don’t always need to open the cap on the radiator. First, check to see whether the liquid reaches the “Full” indicator line on the side of the coolant reservoir tank. This reservoir tank is part of the coolant recovery system. If the liquid doesn’t reach the “Full” indicator line, open the cap of the reservoir and add a 50/50 mix of water and coolant until it does. You can find coolants that are premixed. A premixed solution is recommended to ensure the proper percentages of both water and antifreeze are present. Check the side of your bottle of coolant to see if you have premixed or if you will need to add water yourself.

Never add only water to your coolant system except in an emergency. The reason for this is because most modern engines have cylinder heads comprised of aluminum. These aluminum cylinder heads require the anticorrosive properties found in your antifreeze. Remember to use a 50/50 mixture every time.

Use Caution!
Some of these coolant reservoirs are pressurized and have a radiator pressure cap that can seem to “pop” off when you’re opening the reservoir tank. If you own an older vehicle, your car may not have a coolant reservoir, so in order to check your coolant levels you will have to open the cap on the radiator itself.


If you find that you need to add more liquid, wait until the engine has cooled down. This prevents the possibility of being burned or cracking your engine block. Even if you encounter trouble on the side of the road and need to simply add water before reaching a repair shop, wait until your engine cools. Additionally, do not open the caps on either the coolant reservoir or the radiator while the engine is hot, even just to check levels. If you do, especially in a pressurized system, hot coolant may be ejected.

Additional notes on antifreeze:
• If your coolant look colorless, rusty, or has foreign objects floating in it, you will need to completely flush your cooling system and add a new 50/50 mixture.
• If you notice that your antifreeze mixture has a sludgy or oily surface, be sure to immediately take your vehicle into a mechanic. They will need to check for internal head gasket leakage and have specialized tools to perform this check.
• Feel your radiator hoses. If they’re leaking, bulged, or cracked- replace them immediately.

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  • thankyou for such a good piece of information i find this here because i have read about antifreeze called ethylene glycol in my chemistry textbook

  • Thank you for the info that was exactly what I needed, again thank you so much…

    • I’m glad I read the information for coolant antifreeze. I didn’t know that the coolant keeps the engine cool. I have a 1996 Ford Taurus for 25 years. I bought it in 1997 at 18,000 miles. its has 119,470 miles. I been checking the cooling reservoir every so often to its level as well as he other fluids, such as steering wheel, brake, oil. and transmission. Since I have an older car the servicemen said, it is important to check so my engine won’t blow up. Lots of cars have done that cause the person didn’t pay attention he said. Your information help me to stay focus for my vehicle.