Why You Should Never Use Straight Antifreeze In Your Car or Truck

Antifreeze is a chemical, primarily consisting of ethylene glycol, which when mixed with water serves to lower the freezing point and raise the boiling point of the mixture. Traditionally, the combination of antifreeze and water is known as “coolant” but why should you mix Antifreeze wouldn’t it work better if you used it straight from the bottle?  I decided to find out. Why you should never use straight Antifreeze in your car or truck?

You should never use straight Antifreeze in Your Car or Truck because

  1. Antifreeze made from ethylene glycol freezes between 0 & -5 °- only when it’s mixed with H20 does its freezing point lower
  2. Antifreeze Coolant has no heat-transfer abilities unless mixed with H2O
  3. H2O must be mixed to keep additives suspended

Preparing your vehicle for the winter is also a good time to check your coolant’s antifreeze.  Coolant is the fluid in your radiator while antifreeze is the liquid being added to the radiator to help prevent the coolant from freezing.


Do You Have To Mix Coolant With Water


Air-cooled vehicles rely on fan-driven air blowing over engine components. Water-cooled engines use a radiator, water pump, thermostat, heater core, hoses, and passageways within the engine.

While some antifreeze comes premixed with water, allowing you to simply add more as needed these types of antifreeze can be more expensive. Most are concentrated and need to be mixed with water to achieve the proper level of cooling for an engine but give you the ability to customize the ratio of water and antifreeze to your climate. So what’s the correct formula?

While water is the best fluid for cooling, it can cause corrosion. Antifreeze has a lower freezing point and a higher boiling point than water so it helps protect your engine in extreme weather conditions that normally happen in seasonal temperatures. Using the Antifreeze that is needed to be mixed can give you more flexibility when it comes to the mixture.

A 50/50 mix usually works best for most people in moderate temperatures around the Country where temperatures drop under freezing at certain times of the year. However, in climates where temperatures drop below 32 degrees F for long periods of time, mixtures closer to 70% antifreeze and 30% water are better suited to keep coolant from freezing.

The mixing ratio of water and antifreeze should lie between 60:40 and 50:50. This usually corresponds to antifreeze protection from -25°C to -40°C. The minimal mixing ratio should be 70:30 and the maximal 40:60 Further increasing the proportion of antifreeze (e.g. 30:70) does not lower the freezing point any further. On the contrary, undiluted antifreeze freezes at around -13°C and does not dissipate sufficient engine heat at temperatures above 0°C. The engine would overheat. 

You can apply this calculated amount by using a clean one-gallon milk jug when trying to mix antifreeze and water. Pour the appropriate amount of antifreeze into the one-gallon jug and then fill the original container back up with water. If you’re replacing your coolant, you’ll most likely need more than one bottle– so pour the excess into the milk jug as you mix. Then once you’re done, pour the excess antifreeze back into the proper container.

There are three reasons why pure antifreeze (ethylene glycol) shouldn’t be used at 100% concentration in your car’s cooling system.

The first and perhaps most important reason is that pure ethylene glycol freezes between 0 degrees and minus-5 degrees F. It is only when pure antifreeze-coolant is mixed with water that its freezing point is lowered. So if you need protection from freezing you need to mix antifreeze with water in the proportions suggested by either the car or antifreeze manufacturer. Trying to alter the manufacturer’s suggested proportions only will harm your car.

The second reason is the flip side of the first one. Pure antifreeze-coolant doesn’t have the heat-transfer abilities that a mixture of antifreeze-coolant and water does. In fact, if pure antifreeze-coolant is used in a car’s cooling system, the system loses about 35 percent of the heat-transfer capabilities it otherwise would have when antifreeze is mixed with the proper amount of water.

This is extremely critical in summer driving, especially in our power-accessory-laden vehicles where engine temperatures can soar. The cooling fluid must have the ability to absorb heat and carry it away from the engine – the faster the better. Pure antifreeze-coolant isn’t nearly as efficient at getting the heat out of the engine as is antifreeze-coolant and water. Running on pure antifreeze-coolant will hasten your engine’s demise.

Reason No. 3 is that water must be mixed with the antifreeze-coolant in order to keep the performance additives (silicates, phosphates, and nitrates) suspended. Without water, these important additives tend to settle. If they do that, you lose anti-corrosion and other additive protection. This will also help destroy your car’s engine faster.

That’s also why – although you won’t find it stated on a container – it is a good idea to turn over the container of fresh antifreeze and shake it a time or two before adding it to the cooling system. The little extra shake is insurance that the additives are fully suspended in the container and haven’t migrated to the bottom.

What all this is telling us is that the manufacturers know more about their products than the man in the street does. Like with any type of mechanical device if you’re not sure then ask the manufacturer who has the right answer.


What Does Antifreeze Do For Your Car

The reason you need antifreeze is that your automobile’s engine always runs hot, and it needs a cooling system to keep it at its optimum operating temperature, regardless of whether you’re driving in the dead of winter or during the dog days of summer. This is accomplished by running coolant through channels in the engine block with its flow regulated by a thermostat and a pump, and its temperature kept under control by a radiator usually located at the front of the car or truck.

The coolant needs to stay liquid in order to do its job which keeps your engine at an optimum temperature. If it turns to ice your engine would crack while it’s sitting overnight in cold temperatures. Years of research have to lead to antifreeze/coolant a product when added to your engine resists low temperatures while also fighting corrosion and wear inside the cooling system itself. The Antifreeze needs to be periodically inspected added and changed. Antifreeze is mixed with an ingredient called ethylene glycol when mixed with water can keep your engine from freezing while also help it stay cool.

The most common mixes are 70% water to 30% Antifreeze is recommended in warmer parts of the country. Ethylene Glycol can only attain this ability to resist freezing when water is added to it. With its 50/50 mix can withstand – 50 degrees below 0 before it will start to form crystals and freeze.


Antifreeze Freezing Point

Straight Antifreeze will freeze at 0 and-5 degrees Fahrenheit.  Only by mixing antifreeze with water can you lower than the freezing point. Half the States in our Country experience temperatures that fall below 0 so using straight Anytifreeze wouldn’t work. Not mixing water with Antifreeze would most likely cause damage to your car.

According to automotive experts Pure antifreeze does not have the same ability to transfer heat that a mixture of antifreeze and water does. Using pure antifreeze inside your vehicle’s cooling system causes that system to lose about 35 percent of its ability to transfer heat versus a proper mixture of antifreeze and water.

Mixing water with your antifreeze coolant keeps additives such as nitrates, phosphates and silicates suspended. Otherwise, they will settle inside the system, which could cause you to lose the protection against corrosion that these additives provide.

This is also one of the reasons why it’s a good idea to shake the antifreeze up before adding it into your cooling system—it gets the additives suspended in the container before you even begin dispensing it.

What Are the Different Colors Of Antifreeze



The color of antifreeze is generated completely by coloring dye, not as a direct result of any chemicals mixed during the manufacturing of the product. That said, different colors for antifreeze do exist. Specific colors are agreed upon by the auto Industry. The ingredients are basically the same but there are some basic variations between the products. The main antifreeze colors you’ll run across are traditionally green, extended-life yellow, and extended-life pink or orange. In more recent years, some Korean automakers have even been using blue dye antifreeze.

Use only the color that is recommended by the manufacturer of the car or truck you bought and never mix two different colors. Even when a label sat the mixture is Universal, don’t use it!

Green Colored Antifreeze 

For many decades, virtually all anti-freeze was dyed florescent green and made of ethylene glycol. This type of traditional antifreeze uses “Inorganic Acid Technology” (IAT) as a chemical basis and usually contains silicate or phosphate additives to prevent corrosion of metal cooling system components. This type of Green Antifreeze is highly efficient and less harmful. There has been a movement in recent years to replace ethylene glycol with propylene glycol, which is less harmful if ingested. It’s also less harmful to Pets and the Environment. Green Antifreeze is fairly safe now because of those recent efforts.

Orange & Pink Antifreeze – Organic Acid Technology (OAT) Type Coolants

Antifreeze that’s dyed Orange & Pink features a newer class of corrosion-preventing inhibitors since 1996 that was developed, known as organic acids. They do not contain the silicates or phosphates found in abundance in traditional Green American coolant.

These Organic Acid technologies or OAT Antifreeze products were introduced to America from Europe. They have a longer working life than the standard Green Antifreeze products. This because of the inhibitors that they added before the liquid starts to break down. It’s important to note that organic acid antifreeze should never be used on older vehicles that have traditional copper-and-brass radiators, only aluminum or plastic ones.

How to Mix Coolant with Distilled Water

Tap water from your faucet or hose contains minerals like Calcium and Magnesium which after a while leave residue in the way of deposits throughout your auto’s cooling system. This will particularly around places that heat up. This will eventually block the small passageways inside and cause your engine to overheat. No matter what type of Antifreeze you use or what type of water to Antifreeze ratio you use to mix the formula with Distilled water.

Distilled water has no minerals in it. In the distillation process, the minerals are separated from the water and what’s leftover is water without anything that considered solids that will build up in your car’s engine after running it in high temperatures for a period of time. Distilled Water is sold at the supermarket for about a dollar a gallon.


Propylene Glycol RV Antifreeze

There’s a huge difference between RV antifreeze and automotive antifreeze. RV antifreeze is non-toxic and meant for pumping into the plumbing system. Automotive antifreeze is a whole different type of Antifreeze. Many types are toxic, and should only be put into an engine cooling system. The RV Antifreeze is pink in color and made from two types of chemicals in the world of non-toxic RV antifreeze.

The primary components are either ethanol or propylene glycol. You may remember from your high school chemistry class that ethanol is the  “hooch” in grain alcohol. Yes, ethanol is a good antifreeze not in your bloodstream because it raises the freezing point of water.

That other antifreeze contender, propylene glycol, is also alcohol of sorts. Like grain alcohol, it also raises the freezing point of water. RV folks have a problem with pipes and holding tanks that carry water and may freeze an burst during the winter months so this type of Antifreeze is used to prevent that from happening.

The main ingredient in regular antifreeze is ethylene glycol, which is highly toxic. On the other hand, the main ingredient in RV antifreeze is propylene glycol, which is non-toxic. It’s not hard to handle and virtually safe, unlike Automotive Antifreeze.

  • Does RV Antifreeze Freeze at What Temperature Does it Freeze? RV antifreeze usually doesn’t freeze until the temperature drops to -50. However, it depends on the brand. Basically, the more water that’s mixed with it, the higher the temperature of freezing.
  • Can I Put RV Antifreeze in My Freshwater Tank?  Yes, you can put antifreeze in the freshwater tank. In fact, you should.
  • Where do I Dispose of used RV Antifreeze?  Unlike regular antifreeze, RV antifreeze is non-toxic. That means you can easily dispose of it in a septic system


The health of your Cooling System is important to the health of your car or truck. Antifreeze is much more corrosive when it’s in the form of hot, steaming vapors instead of a normal liquid state. When the Cooling System is not maintained and runs low all kinds of problems develop. Hot steaming vapors fill the empty passageways were the liquid Coolant should be.

This type of environment is toxic and corrosive to the engine affecting the heat transfer creating sludge and running hotter where metal parts continue to get worse. The engineers who created your vehicle designed it to operate full of anti-freeze, so make sure it’s checked and topped off regularly. I didn’t think too much of my Coolant System before I researched a bunch of articles and wrote this article.



JimGalloway  Author/Editor


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