How Long Can I Use Water As Coolant?

The Truth About Water as a Coolant

While the proper coolant mixture is essential for long-term engine health, there may be situations where you find yourself considering water as a temporary substitute. This article explores how long you can use water as coolant and what the potential risks are.

Some experts say there’s no need for engine coolant because water cools better than engine coolant. It’s true that water transfers heat better than a 50:50 mix of water and coolant. But there’s far more to the story than just heat transfer.

Understanding the Role of Coolant In Your Engine

Before delving into the use of water as the coolant, it’s important to understand the function of coolant in your vehicle’s cooling system. Coolant serves several vital purposes:

Temperature regulation: It helps maintain the engine at an optimal operating temperature in both hot and cold conditions.
Freeze protection: It prevents the liquid in the cooling system from freezing in cold temperatures.
Boil protection: It raises the boiling point of the cooling liquid, preventing overheating.
Corrosion prevention: It contains additives that protect metal components from rust and corrosion.
Cavitation protection: Coolant protects against the harmful effects of cavitation
Lubrication: It helps lubricate the water pump and other components of the cooling system.

How Long Can You Use Water as Coolant?

How long you can safely use water as coolant depends on several factors:

1) Climate: In moderate temperatures, water might suffice for a short period (a few days to a week).
2) Driving conditions: Short, infrequent trips are less stressful on the cooling system than long drives or stop-and-go traffic.
3) Engine condition: Newer engines in good condition may tolerate water better than older or worn engines.
4) Water quality: Distilled water is preferable to tap water, which can contain minerals that may cause deposits in the cooling system.

As a general rule, you should aim to replace the water with proper coolant as soon as possible, ideally within a few days and no longer than a week.

Understanding The Risks of Using Water as Coolant

While water can provide temporary cooling, it lacks the crucial properties of antifreeze that protect your engine. Extended use of water as coolant can lead to several problems:

• Freezing: In cold temperatures, water can freeze, potentially causing severe engine damage.
• Overheating: Water has a lower boiling point than coolant, increasing the risk of overheating, especially in hot weather or during high-stress driving.
• Corrosion: Unlike antifreeze, water doesn’t contain corrosion inhibitors, leading to rust and degradation of metal components.
• Scale buildup: Minerals in tap water can leave deposits in the cooling system, reducing its efficiency.
• Cavitation: Water is more prone to cavitation (formation of vapor bubbles) in the water pump, which can cause damage.
• Lack of lubrication: Water doesn’t provide the necessary lubrication for the water pump and other components.

 • Coolant lowers the freezing point

Water freezes at 32°F

• But a 50:50 mix of water and coolant freezes at -35°F

• Coolant prevents corrosion, cavitation, and galvanic reactions

• Water offers no protection against corrosion, cavitation, or galvanic action

• Coolant lubricates and protect cooling system seals and gaskets

Water does not lubricate or protect cooling system seals or gaskets.

Using water instead of coolant damages your cooling system

Because engine cooling systems incorporate dissimilar metals, water acts as the electrolyte to facilitate galvanic action, the transfer of metal ions from one metal to another, resulting in thinning metal and leaks. Water also promotes the oxidation of ferrous metals, resulting in rust formation and heater core and radiator clogging.

Water promotes cavitation

Cavitation damages the water pump housing and impeller, reducing the life of your water pump

Water pump cavitation

Water instead of coolant is a really bad idea

Overall, using water instead of coolant is bad for your engine. It will cause internal corrosion. It can damage the water pump due to lack of seal lubrication and cavitation damage. It can cause your engine to overheat.

©, 2021 Rick Muscoplat