can you mix red and green antifreeze

Can You Mix Red And Green Antifreeze Coolant?


August 10, 2022

Can you mix red and green antifreeze?

Lets find out the answer.

You have a bottle of coolant to refill it, but as you open the antifreeze reservoir, you see that the blue and green hues do not match.

Should you pour in the antifreeze now or wait until tomorrow?

It is not a nice idea to combine antifreeze.

Manufacturers deliberately pick distinct hues to distinguish between chemical compounds.

By mixing the chemicals, you might introduce a chemical reaction that transforms the antifreeze into acid. 

To help you comprehend the topic more, I will explain the distinctions between antifreeze varieties, why mixing antifreeze is not a good idea and their significance.

The Differences Between Red And Green Antifreeze

can you mix red and green antifreeze

Red antifreeze has greater longevity than green antifreeze, as red antifreeze has a longer life span than green antifreeze.

Dexcool, a name given to red antifreeze due to the fact that it extends the life of equipment more than other types of antifreeze, is one example.

The combination of OAT (Organic Acid Technology) and IAT (Inorganic Acid Technology), which resulted in HOAT (Hybrid Organic Acid Technology), was used in the production of red antifreeze.

Red antifreeze is more efficient than green antifreeze in terms of extending the life of your water pump and other cooling system components, which is why it is preferable.

Green antifreeze is a vintage type of antifreeze developed for initial-generation car models.

This is not a high-tech grade of antifreeze technology because of the time period during which it was produced.

Its capabilities are not unique in comparison to today’s antifreeze technology.

The green antifreeze, unlike the red antifreeze created using more advanced technology such as HOAT, is made using (Inorganic Acid Technology) instead.

Green antifreeze consists of inorganic chemicals, making it a C11 type.

They seldom survive more than two years; it is very inexpensive to purchase.

Because green antifreeze has a thick protective layer that protects against leaks and minor cracks in the car’s cooling system, which is made of aluminum and alloys.

The G12 class, which comprises the G12+ and the G12++, contains red antifreeze.

They have a three-year+ shelf life, depending on the blend and preparation method employed before being poured.

Understanding Types Of Antifreeze

can you mix red and green antifreeze

We can still use today’s traditional antifreeze, which was created in 1926 as an ethylene glycol solution.

It is the most poisonous and corrosive combination that is stabilized with additives.

The antifreeze may last indefinitely in an enclosed cooling system with no leaks, but the additives will eventually run out, leaving the antifreeze to corrode components.

At the time, this was not an issue since radiators were copper plated, but aluminum ones had to be cleaned on a regular basis.

Because newer automobiles have aluminum radiators and there is no such thing as replacing antifreeze on a regular basis, using obsolete types of antifreeze might really harm your vehicle.

What Do The Colors Signify?

Some people will tell you that blue represents ethylene glycol, green represents propylene glycol, and red represents organic acid-based antifreeze, but this is not a reliable method of determining what the antifreeze is composed of.

The fact is that antifreeze is colored to make it more visible within the coolant reservoir and easier to find.

When you are looking for antifreeze, the color of the product may help you narrow down your search, but you should double-check the chemical makeup to ensure it is appropriate for your car.

Diluted Vs Undiluted Antifreeze

Antifreeze is available in both undiluted and diluted versions for your convenience.

Adding about 60% distilled water to an undiluted solution is more difficult, but the ease to carry to ship, whereas a dilute solution may be poured straight in the car, which is particularly useful when topping up on the road.

Inorganic Acid Technology

The Z-Grade (Z) and IAT are trademarks of Saint Charles Refrigeration.

They are both a form of corrosion-resistant, potable cooling system that can keep your car cool in even the most extreme weather conditions.

The term stands for Inorganic Acid Technology, which may be abbreviated to indicate whether the antifreeze is suitable for your automobile.

The three most common antifreeze bases are mono ethylene glycol, propylene glycol methyl ether and MPG (mono propylene glycol).

Because of its low toxicity, MPG is mostly used in the food sector, whereas MEG is utilized in almost all car antifreeze solutions.

Propylene glycol methyl ether is utilized for heavy-duty diesel engines the most volatile among the three.

The original green, commonly known as the ‘traditional’ green ethylene glycol solution, is composed of MEG, distilled water, and additives that help to keep the highly toxic and corrosive substance stable.

The original green has been in use for a long time, but manufacturers began to phase it out in the 1990s because of concerns over safety.

The IAT antifreeze should appear bright green, but some manufacturers also used various shades of green and blue to color their solutions.

Heavy-duty diesel solutions are usually colored blue, although they can also be found in red.

Organic Acid Technology

OAT (Organic Acid Technology) solutions, while they do not use silicate or phosphate to stabilize the ethylene glycol, are nevertheless far safer than IAT (Intermittent Ignition Timing) solutions since they do not require any.

The OAT antifreeze is frequently red, although it can also be found in orange, blue, and dark green.

Always check whether the OAT antifreeze you are buying contains phosphates or silicates to determine if it is a hybrid solution.

Hybrid Organic Acid Technology

It is difficult to establish what constitutes HOAT antifreeze, but I believe it consists of the use of silicates, phosphates, or benzoate as solution inhibitors.

It is a hybrid because it combines the inhibitors (additives) from IAT antifreeze with OAT antifreeze.

In terms of hues, HOAT antifreeze is easily distinguished by its brilliant yellow color, although it can also be light or dark blue, pink, or even purple.

Dex-Cool Antifreeze

GM’s Dex-cool is a proprietary antifreeze solution that is compatible with cars manufactured by GM between 1995 and now, as well as some Ford and Chrysler automobiles.

It is a hybrid HOAT solution that promises to offer longer service life.

When it was discovered that Dex-cool causes a slew of gasket failures and acts as a plasticizer, destroying nylon and silicone rubber, it created a stir.

GM settled several class-action suits in 2007 and 2008 and had to compensate owners for the harm, but the 2009 bankruptcy made the payout more difficult.

Now, after years of testing and research, the Dex-Cool solution is made by reputable companies and has been modified and enhanced.

While other antifreeze solutions may be various colors, Dex-cool is consistently bright orange.

Why You Should Not Mix Antifreeze

But let’s get back to our discussion about the color of antifreeze.

I mentioned in previous sections that different antifreeze colors don’t mix together, but there is a very good reason for it.

Even if you manage to replicate the chemical composition, it is unlikely that the antifreeze from another car has the same stabilizers, especially if it is a different hue.

Different additives can counteract each other when mixed together, making the coolant corrosive or turning it into a thicker substance.

Even the same antifreeze hue is not a guarantee that you are receiving the correct combination, according to one expert.

Previously, this might have been true because there was only so much supply, but in today’s plethora of choices, it is unlikely that the two red antifreeze bottles have the same chemical makeup.

My suggestion is that you first see what your car’s manufacturer recommends for antifreeze type or even brand, then stick with it as long as you own the vehicle.

Always get an extra bottle in case you have to fill it up, and it will serve as a useful reminder of what kind of antifreeze to get when you need to clean out the system.

How To Replace Antifreeze

can you mix red and green antifreeze

It is a very straightforward process to change the antifreeze, and you probably have most of the tools you will need.

Some cars come with skid plates that cover the coolant drainage plug, so be careful when removing it.

To remove this, you will need to raise the car using a car jack while also ensuring that there are two jack stands beneath it in case anything goes wrong.

Steps To Replace Antifreeze:

  1. Locate the drain plug, which is usually located under the radiator.
  2. Remove the coolant cap and slide it into the coolant pan.
  3. Allow the coolant to flow out through the plug. To allow for a faster drain, open the coolant cap.
  4. Once it is been drained, replace the plug.
  5. Mix new antifreeze and coolant reservoir carefully. 

You need to add just as much antifreeze as you remove, so check the volume levels in the drainage pan and compare them to what is left in your antifreeze bottle.

If you were able to fill up the cooling system without using all of the antifreeze, there is an air bubble somewhere in the system.

To get rid of it, perform these steps:

  1. Turn the ignition key on and off for a few seconds with the coolant cap removed. This will just cycle the coolant enough to move the bubble toward the cap and expel it.
  2. If that does not work, you will need to compress the coolant hoses at the bends and force the air out that way. You might spill some of the antifreeze, but it is acceptable.
  3. Repeat the two stages until you are confident that all of the air has been removed and the right amount of antifreeze has been used.
  4. Fill the empty bottle of new antifreeze with the old antifreeze, then take it to a disposal site for easy transportation.

How To Measure Antifreeze Concentration

When winter is approaching, it is a good idea to check the antifreeze concentration in your system.

This is a straightforward procedure that can be accomplished with only one simple device.

Steps To Measure Antifreeze Concentration

  1. On a cold engine, open the coolant cap.
  2. Insert the measuring tool into the reservoir and squeeze it.
  3. The tool will suck up the coolant after you release the pressure.
  4. Remove the tester, then take out the antifreeze back into the reservoir and snap on the cap.

Only two options exist if your coolant will not survive a cold winter.

Change the coolant completely, or bleed some of the coolants and add undiluted antifreeze to the reservoir.

I advocate changing it completely because it is not prohibitively expensive and prevents you from wondering.

Frequently Asked Questions

Why does my temperature gauge fluctuate while I am driving?

A fluctuating temperature gauge is a bad sign, and the problem must be addressed right away to avoid engine damage.

The most common causes are a faulty thermostat, a failing water pump, and a low coolant level.

Is it true that there is no difference between red and green antifreeze?

The color of the antifreeze, as we have said in this post, does not have to signify a different chemical makeup, but there is usually a significant difference between the two.

Green an inorganic acid technology antifreeze, which was formerly utilized as a coolant, while red is more often associated with organic acid technology or hybrids.

What color coolant does Chevy employ?

You may quickly verify this by opening the coolant cap and looking at the color of the liquid – Dex-Cool is almost always orange.

To be safe, double-check with the owner’s handbook.

What is the kind of green antifreeze?

In organic acid technology and silicate or phosphate additions, green antifreeze is manufactured approximately 90% of the time.

Green antifreeze was originally produced for cars in the early 1990s or earlier.

Is the coolant color significant?

Antifreeze is not colored to distinguish between the chemical composition; rather, it is used to make it easier to spot leaks and check coolant levels.

Because there are no set color guidelines for antifreeze, manufacturers can choose whatever hue they like because it has no prescribed function.

That is why we may see antifreeze in a variety of hues, including orange, blue, purple, pink, dark green, and others.

Is it possible to substitute orange coolant for green?

Making any significant repairs or modifications to a watercraft engine’s cooling system can be risky.

It is critical that coolant be changed appropriately, and this must not only be done by professional technicians.

Changing from one type of coolant to another may have a similar effect on the system as mixing them together.

Coolant passes through the system while coming into contact with aluminum, plastic, steel, rubber, and other materials.

Incompatible types of coolant might eat through some of these materials, harden rubber, and cause a variety of problems that could be very costly to repair.

Is it acceptable to add a new coolant while still having an old one?

If your levels are low, you can top off the old coolant with fresh; but when replacing it, always completely drain the system.


Whether you need to top up or replace your antifreeze, stick with the same type and never mix them.

Mixing colors may severely damage the engine, yet there is no reason to do it since all forms of antifreeze cost around the same.

If you run out of coolant on the road and there is no specific type available, just purchase distilled water instead.

It will dilute your cooling system, making it less resistant to boiling and freezing, but it will get you home where you can flush the system or add 100 percent antifreeze to make up for it.


Jeffrey Bryce is an experienced motorcycle rider with years of experience caring for motorcycles. His natural fondness for motorcycles have made him come up with, which is dedicated to answering and teaching you how to care for your bike with the care it requires. LetsGoForARide is the one of his important lifework in reaching out to communities of motorcycle enthusiasts on how to take care of their bike and choosing the correct spare part.