Antifreeze is contained in the engine coolant to prevent the engine from freezing.

There are times when you have little antifreeze and the only brand available is different from the one you used before.

Many drivers are unsure about mixing the two brands because the ingredients are different.

Most antifreeze products use ethylene glycol as the main coolant base. The green/yellow color found in most antifreeze is due to the use of silicates, but new antifreeze variants made from organic acids give an orange or pink color.

If you mix one of the two variants, you reduce the corrosive properties of the antifreeze.

Antifreeze is available cheaply in stores, and you should simply flush the coolant in the cooling system with a new brand instead of mixing the two.

What is the purpose of antifreeze?

When antifreeze is added to the cooling system, it lowers the freezing point of the coolant. This has the advantage that water does not turn to ice at extremely cold temperatures. It also prevents the engine from overheating by increasing the boiling point of the coolant. Antifreeze reduced corrosion of your engine and supports heat transfer.

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What are the various types of coolants?

Zerex G-05 Antifreeze

The answer to the question of mixing different coolants is more complex than it sounds. You don’t have to consider the color of the coolant, but the type of coolant and the type of engine you have. Read on for more information on how to be sure you can mix coolants.

There are many different colors when it comes to antifreeze. However, there are two specific colors that you should pay special attention to.

Green coolant

This was previously the only type of coolant available. It is produced by inorganic addiction technology (IAT). In this case phosphates are added to ethylene glycol; some use propylene glycol instead.

Orange coolants

This is produced by organic acid technologies. The new coolants have been developed to meet the production of newer cars where aluminum and nylon parts were used.

When the two types of antifreeze are mixed, a thick gelatinous substance is found in the engine. Instead of acting as a coolant, the antifreeze mixture causes further overheating of the engine. Damage can extend to the water pump, the gasket, and the radiator. If the problem is not corrected, you will need to make further engine repairs.

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Examples of anti-freeze compounds


Methanol is a volatile, colorless liquid known as the simplest alcohol. Although it is not suitable for use in automotive antifreeze, its solvent properties allow it to be used as a windscreen washer at room temperature.

Ethylene glycol

This is the most popular antifreeze. It has a high boiling point, which makes it the perfect agent for antifreeze mixtures. It can oxidize with other chemical compounds, which has led to more and more manufacturers using propylene glycol. Ethylene glycol is also toxic and should never be ingested, even though it has a sweet taste.

Propylene glycol

It is used as a substitute for ethylene glycol because it is less toxic. This has led to its use as an anti-freeze compound in various consumables such as ice cream or processed foods. Propylene glycol oxidizes when exposed to air, and other compounds are used with it to prevent corrosion of metal parts in the engine.

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How do I measure the freezing point of coolant?

Antifreeze prevents your coolant from freezing. If the radiator leaks, the antifreeze loses its effect. There are three ways to check the freezing point of your antifreeze mixture: Test strips, a refractometer, and specific gravity.

Refractometers are often quite cheap, and if you want to get one, you can check out this one on Amazon.

Antifreeze can maintain its effectiveness indefinitely if there are no leaks. But the moment the radiators start leaking, the corrosive inhibitors are used up, so they have to be replaced constantly. It is recommended to flush the coolant at the next engine service and replace the antifreeze with a new one.

How to use the anti-freeze

Coolant Reservoir

The first thing you need to confirm when buying your antifreeze is that it is not diluted. A concentrated mixture of 50 percent distilled water and 50 percent coolant should be prepared. If you expect temperatures to drop below -34 F, you may need a higher ratio of the antifreeze. Tap water is not recommended for dilution to its mineral content; use deionized or distilled water.

It is recommended to change the antifreeze every two years, however, this may vary depending on the manufacturer’s instructions.

Internal combustion engines generate a lot of heat by igniting the air-fuel mixture. Excessive heat can destroy most metal parts of the engine. To cool the engine, a system of pipes and a coolant help to carry the heat away from the engine to the radiator, where it is cooled.

The antifreeze mixture often contains some corrosive inhibitors to protect some of the metal parts in the engine. These include cast iron, aluminum, brass, copper, and brazed parts. Water has been used as a coolant over the years, but it has its flaws.

Firstly, it solidifies under extremely cold temperatures, which can cause the engine block to solidify and become damaged. Freezing pins are often placed in engine blocks where the coolant is known to flow. When the engine block freezes, the plugs are pushed out. When they started mixing the coolant with antifreeze, the first compound used was methanol. However, since most radiators were vented, methanol evaporated through the radiator seals, requiring constant replacement.

The radiator caps were later sealed. Methanol also had the disadvantage that it caused corrosion on the engine metals made of aluminum. Later, ethylene glycol was developed as the main antifreeze. A major change in radiator gaskets in the 1950s led to the development of the radiator cap, which allowed pressurized coolant. This helped the coolant cope with high engine temperatures.

Due to environmental concerns, the main component of the coolant was replaced by ethylene glycol.


The question of whether antifreeze should be mixed is controversial. Some people think that it does not harm the engine, but there are those who have noticed a liquid gel when mixing the green and pink coolant. Both types of coolants use different corrosion inhibitors, and these can react and damage your cooling system.

Antifreeze is relatively affordable, and there is no harm in flushing the cooling system of the previous fluid and filling a new bottle. Always be sure to check the radiator cap for leaks, as this can reduce the effectiveness of the antifreeze.