Antifreeze is not only for use in cold climates, its properties can help to maintain and preserve your car’s cooling system as well as the cooling channels in the engine block.
While it is possible to use pure tap water in your car’s radiator, it is not advisable.
The lack of antifreeze may also void the warranty on your car as well as any cover you may have with your insurance company.
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What Happens if You Don’t Mix Antifreeze with Water?
If you fail to mix the correct amount of anti-freeze with the water in your radiator, you can sustain damage to the cooling system when the water freezes and expands. Antifreeze also contains additives that lubricate and prevent scale and rust build-up in the pipes and channels in your engine.
As engines have become more sophisticated, the amount of heat generated during combustion has increased. This heat is carried away from the engine by the engine coolant.
Ethylene glycol and propylene glycol are the preferred components in engine antifreeze, as they both lower the temperature at which the water/antifreeze mixture freezes as well as increase its boiling point.
When you consider that engine combustion temperatures can reach more than 4,000°F (2,204°C) and the melting point of aluminum is 1,1917.4°F (660,3°C), you can see why it is important that the heat is efficiently reduced.
Why Antifreeze is Mixed with Water
Mixing antifreeze with water adds a greater margin of safety to both the boiling and freezing point of your vehicle’s engine coolant.
Antifreeze Increases the Coolant’s Boiling Point
Water has a boiling point of 212°F (100°C). Adding ethyl glycol antifreeze increases this temperature to around 223°F if it is mixed at a ratio of 1:1.
That is very close to the normal operating temperature of your engine.
But your car’s cooling system is pressurized. This pressure increases the boiling point of the coolant by a further 3°F (1.67°C) for every pound of increased pressure.
With the cooling system pressure being around 15-PSI for the average car, the boiling point of the coolant mixture is increased further to around 268°F (131°C).
This gives your car’s cooling system added protection in very hot climates where the higher temperatures may cause the engine to overheat if its coolant consisted of only water.
Antifreeze Decreases the Coolant’s Freezing Point
Tap water will freeze at 32°F (0°C). Once you add antifreeze, the temperature at which the coolant freezes drops. It will then depend on how much antifreeze you add to the water before you can determine its freezing point.
A mix of 50% water and 50% antifreeze drops the mixture’s freezing temperature down to -35°F (-37.2°C).
The practical application of this principle is, that cars with antifreeze in their cooling systems can withstand temperatures well below freezing, without their coolant freezing.
If the coolant freezes, it expands to a point where it will damage the radiator, water pump, the cooling system hoses, and the cooling channels in the engine block.
Safety Warning!
Whenever you add coolant or wish to check the coolant level, allow the engine to cool down first before loosening the radiator cap.
You should check the expansion bottle first, anyway, before moving on the radiator.
Even if the car is not overheating, the temperature inside the radiator will be lower due to the increased pressure in the system and the antifreeze.
Once you release the pressure by opening the radiator cap, the coolant will quickly reach temperatures well beyond water’s normal boiling point.
This causes the coolant to spray out of the radiator spout violently. If you are unfortunate enough to be standing over it, you will receive third-degree burns from the scalding water and steam.
What is Coolant Made Of?
The coolants that are available to put in your car are all glycol-based.
You’ll find that each brand is very much the same except for slight changes in the additive packages that the manufacturers put in them.
Propylene glycol is preferred over ethylene glycol due to its less toxic makeup.
Water Carries More Heat Than Antifreeze
One of the reasons why you don’t want to only put antifreeze into your radiator is that it is not capable of carrying as much heat as water. The cooling capacity of your system may be decreased by as much as 35% if you only put antifreeze in the radiator.
But you don’t want to just put water into your radiator either. If you do, it will cause the engine to rust.
The rust that forms on the iron parts of the engine will be washed into the rest of the cooling system, forming sludge and clogging the cooling channels in the engine and the radiator.
The cooling system acts as a heat exchanger. It carries the heat produced by the engine in the coolant to the radiator. The air flowing across the fins in the radiator cools the liquid by extracting heat.
If the corrosion causes sludge to build up, it prevents the heat transfer from taking place.
The additives in the coolant help to protect the engine from corrosion so that it will last longer and operate efficiently at the right temperature.
The Three Types of Antifreeze
Antifreeze comes in three broad categories;
- Inorganic acid technology coolant (IAT)
- Organic acid technology (OAT) coolant
- Hybrid organic acid technology (HOAT) coolant
Inorganic Acid Technology (IAT) Coolant
This coolant is found in older vehicles and you must change it fairly frequently as it loses its cooling properties quickly.
I recommend that you replace IAT coolants every 24,000 miles (34,00 km) or within two years, whichever comes first.
There are newer formulas that extend the coolant’s lifespan to anywhere between three and five years.
These coolants are either green or yellow in color.
Organic Acid Technology (OAT) Coolant
Organic acid technology coolants make use of organic acids to protect the engine from corrosion and are usually orange in color.
Depending on the additional chemicals that are present, the color can be dark green, pink, or even blue.
Their lifespan is around five years or 50,000 miles.
Hybrid Organic Acid Technology (HOAT) Coolant
Hybrid organic acid technology (HOAT) coolants are a combination of the previous two coolants.
Most new vehicles use this type of coolant, but you need to read your owner’s manual to check that you are selecting the right one for your engine.
These coolants last longer than the others and can be changed at five-year intervals or after 50,000 miles.
The Different Types of Hybrid Organic Acid Technology (HOAT) Coolants
HOAT coolants come in a variety of blends, with each blend targeting a particular type of engine.
The additives used can damage certain engines, so it is important that you not mix them up.
Using the wrong coolant can result in poor performance or, at worst, engine failure.
Phosphate-Free HOAT or Hybrid OAT Coolants
Phosphate-free HOAT (hybrid OAT) is a coolant that contains mono-ethylene glycol.
It inhibits corrosion through the use of organic and inorganic corrosion inhibitors. It is low in silicate and is NAP-free.
Due to these chemicals causing damage to various engine components, there’s no borate, nitrate, nitrite, or phosphate present in the mix.
You can tell it apart from other coolants by its turquoise color.
Most European vehicle manufacturers specify phosphate-free HOAT coolants.
Phosphated HOAT Coolants
This pink or blue-colored coolant makes use of phosphates, carboxylates, and organic acids to reduce and prevent corrosion in engines.
Due to its ability to cope better with higher ambient temperatures, it is often specified for cars manufactured in Asia.
Silicated HOAT (SI-HOAT)
Silicated HOAT coolants make use of organic silicate technology to provide engine protection and superior antifreeze ability.
It does not have borate, amines, phosphate, nitrites, nitrates, or imidazole present in the formula. It relies on silicates and organic acids to reduce corrosion and provide cold weather protection.
High-end European luxury and performance cars specify this coolant to protect their engines.
How Often Should You Change Your Coolant?
Each manufacturer recommends different coolants for specific models within their ranges.
It is best to consult the owner’s manual to confirm both the type and the mileage, after which you should change the coolant.
A general rule is to change your coolant after every 50,000 miles, but some newer, high-performance vehicles require a coolant change as often as every 10,000 miles.
When changing the coolant, it is important to drain as much old coolant out of the cooling system as possible.
This will ensure that any sludge or rust particles and other contaminants are removed from the system.
You should also avoid mixing different types of coolant as they can react with each other and cause accelerated corrosion of plastic, rubber, and metal parts of the cooling system and engine.
When you change your coolant, it is a good idea to clean and check your radiator cap to make sure it is fitting properly and is not damaged in any way.
Frequently Asked Questions on What Happens if You Don’t Mix Antifreeze with Water
What happens if you use undiluted antifreeze?
Undiluted antifreeze does not work as well as a mixture of antifreeze and water. It will not transfer heat as effectively as it should and can lead to the engine overheating.
Is antifreeze the same as coolant?
Antifreeze and coolant are terms used interchangeably. They refer to the fluid that is mixed with water to protect your engine from both heat and cold. Every car has a recommended type of coolant that should be used. It’s best to check the owner’s manual to make sure that the correct antifreeze is being used.
What color should antifreeze be?
Antifreeze should be a clear, brightly-colored liquid. Each type of antifreeze comes in a slightly different color, from blue, green, and red to orange, violet, and yellow. Old antifreeze will become dark and can become slightly brown from iron oxidation (rust).
Conclusion About What Happens if You Don’t Mix Antifreeze with Water
It is vital that you mix antifreeze with water in the correct ratio, for it to do its job properly.
Choosing the right coolant for your vehicle is important, as the incorrect antifreeze can damage your engine.
To be sure, check the owner’s manual for the correct antifreeze formula for your car.