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Can You Use Water As Coolant? We Chill Up Some Details!

Last Updated on: June 9, 2024

Have you ever thought of using water instead of antifreeze in the coolant tank of your car? 


You aren’t alone. Many individuals feel that distilled water instead of coolant is acceptable, particularly in hot climates. 

For instance, if the temperature never drops below 32 degrees Fahrenheit, why do you need fluid to keep it from freezing? So, is it safe to replace the coolant with water?

Water is less expensive and may help avoid overheating, but coolant is helpful for more than that. It is essential for the effective operation of the car’s cooling system. 

Let us take a closer look.

How A Coolant Works

The engine generates heat as you drive your vehicle and must be constantly cooled to function correctly. If you do not cool the machine down, it will stall. The cooling system pumps coolant into the passageways and the cylinder heads of the engine block. As it moves through the engine, the coolant absorbs heat.

The car radiator fluid from the engine will receive heat. As it flows through the radiator’s tiny tubes, air from the front of the automobile cools it. The fan is also running to keep the correct temperature of the radiator. After cooling in the radiator, the fluid returns to the engine.

This coolant circulation is what powers the cooling system.

Differences Between Water And Coolant

1. Boiling Point

Boiling Point

Few people consider the variations in boiling points between water and coolant. However, your vehicle’s operating temperature will be higher than the boiling point of water (212°F).

The boiling point of ethylene glycol antifreeze increases to 223°F when mixed 50/50. That value is significantly closer to the operating temperature of the engine. 

When using a waterless coolant, the boiling point rises to 375°F or higher.

The vehicle’s engine will overheat without antifreeze. The liquid within will boil over and evaporate, requiring you to pull over to the side of the road so the engine can cool down. 

Allowing the engine to overheat might potentially cause catastrophic and serious damage.

2. Freezing Point

Freezing Point

If you reside in a colder environment, the reverse is true. It will go beyond the freezing point and freeze if there is no antifreeze in the cooling system.

When your radiator freezes, you’re in for a lot of trouble. Your radiator may shatter, leaving your engine’s cooling system inoperable.

3. Corrosion Protection

Corrosion Protection

Over time, the minerals in the water will build up in the radiator, causing it to stop working correctly. Rust formation will occur more quickly since water is corrosive to metal.

Because these conditions are dangerous to your vehicle’s engine, coolant contains anti-rust compounds. Always use pure water to prepare antifreeze since it is devoid of pollutants.

Metal components are well-protected with the best composition, ensuring a long service life.

Using Water Instead Of Coolant

When you only have access to water, you can use it instead of coolant in an emergency. After correcting the leak, immediately refill the system with the proper coolant mixture. 

In the long term, never drive with simply water.

Even if you live in a warm area, using water solely for lengthy periods is not advisable. 

If you solely use water, then it might create internal corrosion, overheating, and other problems with your engine!

What A Coolant Or An Antifreeze Is

Anti-freeze or coolant system

Sometimes, people use Coolant and Antifreeze interchangeably due to their minor differences.

Ethylene or propylene glycol makes antifreeze, which keeps the coolant in liquid form for optimal protection.

Coolant is made by mixing antifreeze and distilled water in a 50/50 ratio. 

It comes in many hues, including green, pink, yellow, red, blue, and orange. These colors make choosing which antifreeze is best for your car easy.


1. Inorganic Acid Technology (IAT)

IATs are the most outstanding solution for older vehicles manufactured between the 1920s and the mid-1990s. They are often a bright green hue.

Every 30,000 miles or two years, whichever comes first, you should replace the IAT. It has anti-corrosion properties that protect metal components like the radiator and engine.

2. Organic Acid Technology (OAT)

The color of OAT, the most frequent and widespread variety in most contemporary automobiles throughout the world, can range from orange to dark green and is a container containing corrosion inhibitors and chemicals to prevent rust development.

OAT is substantially more durable than IAT. Every 150,000 miles or five years, whichever comes first, must be replaced. There are several instructions for changing your engine coolant.

3. Hybrid Organic Acid Technology (HOAT)

HOAT is frequently orange or yellow. It was created specifically for new automobiles and blended with the previous two, with additives for increased aluminum protection and rust prevention. HOATs have a lifespan of 150,000 miles or five years, much like OAT coolant.


Ethylene glycol-based antifreeze is toxic to people, pets, and wild animals, even in small concentrations. Antifreeze of this sort is a thick, odorless liquid with a nice flavor.

  • Two ounces is sufficient to kill a dog.
  • One spoonful of antifreeze may kill a cat.
  • Two tablespoons may be harmful to youngsters.

It breaks down into acid, which accumulates in the kidneys and destroys them by generating calcium oxalate crystals if they swallow the chemical. Kidney damage causes acute renal failure.

Use propylene glycol-based coolants if you have small children or pets in the house and want to be extra cautious. This antifreeze liquid is only dangerous in large quantities.

Importance Of Coolant

When the heat generated by an internal combustion engine builds up, it can lead to costly complications. The head gasket might fail, but the cylinder head can also warp, resulting in severe engine damage.

The liquid evaporates and boils away when water is used in the motor, leaving the vehicle without fluid. However, the water is more likely to freeze in cold areas, resulting in a radiator fracture, cracked engine block, or heater core failure. Each automaker’s cooling system is unique, necessitating a specific coolant to ensure comprehensive protection. 

If you don’t use the recommended antifreeze, then you can cause more harm than good!

Proper Way To Add Coolant

Man pouring coolant inside radiator

You should check the coolant levels before you begin. When the engine is hot, don’t open the radiator cap because pressure has built up within, resulting in hot liquid splashing as you remove the lid.

Open the coolant reservoir cap once the engine has cooled. You can glance inside or read the marks on the tank’s side to check the level. If more coolant is needed, follow the manufacturer’s directions and mix the antifreeze with clean water. If you buy a pre-mixed coolant, you may skip this step.

Fill the overflow tank with coolant, but don’t overfill it because this fluid expands when it becomes hot. If your car lacks an overflow tank, pour it directly into the radiator, but don’t go over the “full” mark. Replace the cap and start the engine. At this time, you should also check for leaks in the radiator and hoses. 

Maintaining your cooling system with the proper fluid ensures that your engine operates smoothly.

Pro Auto Thought: The idea behind a coolant is to maintain proper heat distribution and dissipation so that your car engine won’t get damaged by overheating. The next concern to deal with is how to determine how low a coolant could get — Does Low Coolant Affect Air Conditioning.

Watch This!

Frequently Asked Questions

What happens if you use water instead of coolant?

The higher engine water temperatures will cause it to boil quickly and evaporate, resulting in coolant loss and overheating.

Can I use normal water for coolant?

No, you can’t. I do not recommend this approach for long-term use or under harsh conditions since water freezes at 0 degrees Celsius.

Can you use bottled water as coolant?

What is the purpose of using bottled water to cool engine oil? Unless the radiator is in the automobile, you should not use distilled water. 


You may confidently answer, “Can I use water instead of coolant in an emergency?” now that you know what coolant/antifreeze is, how many sorts there are, and why it’s essential to your car’s engine.

Only use water for cooling in an emergency. However, I do not recommend this since water beyond its boiling and freezing temperatures would not perform effectively.

Long-term use of water as a coolant might result in expensive engine damage. As a result, only use it when required. Regularly check the coolant level and cooling fan to avoid future cooling system issues.

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