Selecting the right radiator coolant additive is essential for maintaining engine performance and ensuring long-term reliability. This article provides a neutral, fact-based comparison of three popular coolant additives, focusing on their features and benefits.
Understanding Radiator Coolant Additives
Radiator coolant additives are important for maintaining engine performance and longevity. Here’s a clear overview of their purpose, function, benefits, and when to use them.
1. Purpose
- Engine Protection: Radiator coolant additives are primarily used to enhance the protection of the engine’s cooling system. They help prevent overheating and potential damage.
- Improved Heat Transfer: These additives are designed to optimize the coolant’s ability to transfer heat away from the engine, ensuring that it operates within a safe temperature range.
2. Function
- Performance Improvement: Coolant additives improve the ability of the coolant to absorb and transfer heat. This helps to lower engine temperatures, promoting efficient operation.
- Damage Prevention: By maintaining proper engine temperatures, the additives help prevent overheating, which can lead to serious engine damage or failure. They also help reduce the risk of leaks in the cooling system.
3. Benefits
- Corrosion Prevention: A key advantage of using radiator coolant additives is their ability to prevent rust and corrosion within the cooling system. This extends the life of engine components, including the radiator and hoses.
- Compatibility: Most coolant additives are compatible with various water sources, such as distilled, tap, or treated water, ensuring ease of use across different applications without causing adverse reactions.
- Overall Engine Efficiency: By keeping engine temperatures stable and preventing damage, these additives contribute to improved engine efficiency. They can result in better fuel economy and overall performance.
4. When to Use
- Extreme Temperatures: Using coolant additives is particularly beneficial in environments with extreme temperatures, whether very hot or very cold. This helps to enhance the coolant’s effectiveness in protecting the engine.
- Older Engines: Older engines often benefit more from coolant additives as they can restore lost efficiency and offer additional protection to aging components.
- Routine Maintenance: Incorporating coolant additives during regular maintenance checks is advisable. This practice helps ensure ongoing protection and enhances the cooling system’s performance.
By understanding the role and benefits of radiator coolant additives, engine owners can make informed decisions about their cooling systems and help maintain the optimal performance and longevity of their engines.

Difference Between Standard Antifreeze Coolant and Radiator Coolant Additives
- Standard Antifreeze Coolant:
- Primarily regulates engine temperature.
- Lowers the freezing point and raises the boiling point of the liquid.
- Helps prevent freezing and overheating.
- Radiator Coolant Additives:
- Designed to enhance the performance of existing antifreeze.
- Improves heat transfer.
- Reduces corrosion and protects engine components from wear.
Conclusion:
While antifreeze can be used alone, coolant additives should be mixed with antifreeze for added benefits, ensuring optimal engine protection and efficiency.
Red Line Water Wetter
- Key Features:
- A cooling system additive that lowers coolant temperature and improves heat transfer.
- Contains surfactants to reduce surface tension in the coolant.
- Performance: Effective in preventing cavitation and foaming while providing enhanced cooling properties. Some users report noticeable decreases in operating temperatures but must follow manufacturer recommendations for application.
Royal Purple Purple Ice
- Key Features:
- A coolant additive designed to improve thermal stability and reduce engine temperatures.
- Compatible with all antifreeze and coolant types.
- Performance: Known for its ability to reduce the formation of scale and corrosion, contributing to an efficient cooling system. Users appreciate its effectiveness but should ensure proper mixing with existing coolants.
AMSOIL DOMINATOR® Coolant Boost
- Key Features:
- Formulated for both racing and everyday automotive applications.
- Helps lower engine temperatures by up to 25°F (13.8°C.)
- Performance:
- Uses proprietary tiered-surfactant technology to enhance heat transfer within the engine.
- Designed to prevent corrosion and provide extended protection for components like the heater core, radiator, and water pump.
- Application:
- For straight-water coolant systems, use 2 fluid ounces of Coolant Boost per quart of system capacity.
- In antifreeze applications, use 1 fluid ounce per quart of coolant system capacity.

How to Use Radiator Coolant Additives
- Preparation: Ensure the engine is off and cool before adding any coolant additives.
- Application: Shake the additive bottle well, then pour the recommended amount into the radiator or coolant reservoir.
- Run the Engine: Start the engine and allow it to run for approximately 15 minutes to circulate the additive throughout the cooling system.
Maintenance Recommendations
- Routine Checks: Regularly monitor coolant levels and condition, ensuring that additives remain effective.
- Follow Manufacturer Guidelines: Always adhere to the vehicle manufacturer’s recommendations for coolant change intervals and types.
Conclusion
Choosing the right radiator coolant additive is critical for maintaining engine temperature and preventing corrosion. By incorporating high-quality coolant additives into your maintenance routine, you can prolong the life of your engine components and ensure reliable performance. Always consult your owner’s manual for specific recommendations on coolant systems and additive applications for optimal results.