AUTONEWS

This winter mistake can prove costly for drivers: Mechanic warns of serious engine damage
Plain water in a car's cooling system freezes at zero degrees and boils at 100 degrees Celsius, yet an engine can easily reach high temperatures while running. American mechanic Scotty Kilmer warns that using only water instead of antifreeze can cause serious—and potentially irreparable—engine damage. Experts therefore recommend using an appropriate mixture of antifreeze and water, most commonly in a 50:50 ratio.
Coolant—commonly known as antifreeze—serves several vital functions within an engine, more than is generally realized. As reported by Autonews, citing American mechanic and YouTuber Scotty Kilmer, using plain water instead of antifreeze can pose a serious threat to the engine, especially during the colder months, Autonews notes.
The reason is simple: water freezes at zero degrees and boils at 100 degrees Celsius. Antifreeze lowers the freezing point and raises the boiling point of the coolant, thereby protecting the engine both while driving and when the car is parked.
Why do I need coolant/antifreee? As the name suggests, coolant/antifreeze is necessary to reduce the freezing point of your engine’s cooling system and raise the temperature at which the system will boil when compared to water alone.
The boiling point of water is 100-degrees C. The accepted pressure range for a car’s radiator is between 75-100kPa (or 11-15psi) and with a mix of 33% coolant/antifreeze to water the boiling point is raised to 121-125-degrees C. Change the ratio to 55% and this lifts to 125-129-degrees C.
If you live in a cold climate where the temperatures regularly (in winter) drop below freezing, then the accepted ratio of coolant/antifreeze to water is 60:40. Oddly, increasing the amount of antifreeze in the system will actually reduce its protective qualities. So, with 60% coolant/antifreeze in the system the temperature at which the first ice crystals will begin to form in the cooling system is -55-degress C. With no antifreeze/coolant in the system (and just straight water) ice crystals will form at 0-degrees C. Letting the engine’s cooling system freeze will see the fluid expand and crack engine blocks and blow the radiator apart.
But, even in Australia, the use of coolant/antifreeze to protect against freezing is vital. See, wind chill can accelerate the ‘heat loss’ of your car engine’s cooling system. For instance, say the ambient temperature is 0-degrees C (a regular winter temperature in the Blue Mountains where I live) driving at just 24km/h will cause wind chill to reduce temperature of the air hitting the radiator to -21-degrees C and at 60km/h the temperature would end up being -30-degrees C. Beyond 60km/h the wind chill factor effect becomes minimal. That said, windchill will not actually reduce the temperature of your engine’s heating/cooling system below ambient temperature, but it will speed up heat loss. So, with a 60:40 mix of coolant/antifreeze:water protection against freezing will extend to -55-degrees C.
Can I use water instead of coolant? No. Well, maybe not. The idea of running coolant in your car’s engine is to increase the boiling point of the water which is being pumped around your car’s engine and through the radiator where the air flowing through a moving car’s radiator cools down the water as it continues on its way back through the engine.
In Australia...Depending on where you live in Australia, your water will either be harder or softer than somewhere else. All water contains dissolved salts and minerals, which if running straight water in your engine (without coolant), can reduce the life of some components. So the argument is one that’s less about cooling properties and one about the potential damage water can do to your car’s cooling system.
In colder climates (see paragraph above), using just water means the car engine’s cooling system will freeze at 0-degrees C, and when water freezes solid it expands, which can lead to cracked engine blocks or burst radiators.
Why is plain water not enough? While water is effective at transferring heat, its major drawback is that it freezes at low temperatures and boils at high ones. Antifreeze is specifically designed to prevent these issues and protect the engine across a variety of weather conditions. Kilmer, who has over 6.4 million subscribers on YouTube, also warns of another issue: cavitation.
"There is a reason why the cooling system should be filled with a mixture of half antifreeze and half water," he explains.
According to him, antifreeze prevents freezing during the winter and protects the engine from cavitation—a phenomenon that can cause serious damage. Cavitation occurs when vapor bubbles form within the liquid and then suddenly collapse, generating pressure that can damage the engine's metal components. Antifreeze contains additives that help protect against this, whereas plain water does not. Consequently, driving for an extended period with only water in the cooling system can lead to costly, or even irreparable, engine failure.
An example involving a Toyota with a completely failed engine...As a cautionary tale, Kilmer cites the case of a Toyota owner. The previous owner had used only water in the cooling system, and the new owner was unaware of this. The result was a complete engine failure. This example illustrates how important it is to know what kind of fluid is in the cooling system, especially when purchasing a used car.
Kilmer’s message to drivers is clear: "So please, never drive a car that has only water in its cooling system."
Even tap water is not a good solution...A similar warning comes from the website BookMyGarage, which specializes in comparing prices for car repairs and maintenance. Experts advise drivers to regularly check the composition of their engine coolant. Tap water is not suitable for this purpose, as it may contain minerals that contribute to the formation of deposits and damage components of the cooling system.
A mixture consisting of 50% antifreeze and 50% water is most commonly recommended; however, it is important to follow the vehicle manufacturer's guidelines and use the appropriate type of coolant.
"Using water instead of coolant on a regular basis can lead to very costly repairs," experts warn.
What should drivers keep in mind? Antifreeze is not merely a substance used to prevent an engine from freezing during the winter. It also plays a crucial role in protecting against overheating, corrosion, and cavitation. For this reason, drivers are advised to regularly check the level and condition of their coolant. Furthermore, when purchasing a used car, they should pay attention to what is inside the cooling system.
It is also important to check the coolant only when the engine is cold, as opening the system while the engine is hot can result in serious burns.
To prevent water from freezing in winter or boiling due to engine heat, cars use a mixture of demineralized water and a radiator additive (typically based on ethylene glycol), along with a pressurized cooling system.
This combination alters the physical properties of the liquid, allowing it to withstand the extreme conditions within an engine:
1. The effect of the additive (ethylene glycol)... When the additive is mixed with water, a chemical phenomenon occurs that changes the liquid's freezing and boiling points:
• Elevation of the boiling point: The mixture will only boil at approximately 105°C to 110°C (under normal atmospheric pressure).
• Lowering of the freezing point: The water no longer freezes at 0°C; instead, it can withstand temperatures as low as -35°C (depending on the mixing ratio) without turning into ice.
2. The secret of pressurization (pure physics)... A car's cooling system is completely sealed and operates under high pressure.
• In a closed environment, as the liquid heats up, the internal pressure increases.
• In physical terms, the higher the pressure exerted on a liquid, the higher its boiling point becomes.
• Thanks to the radiator cap (or the expansion tank cap), which maintains this pressure, the boiling point of the mixture rises even further, reaching between 125°C and 135°C.
Since an engine typically operates between 90°C and 105°C, the liquid is able to absorb and dissipate all this heat without evaporating or boiling.













