Looking for the best coolant additives? Discover top picks like Royal Purple Purple Ice and Radiator Relief that slash heat, prevent leaks, and extend engine life for cars, trucks, and PCs.
Coolant additives are engine heroes. They keep vehicles cool, protected, and running longer.
Royal Purple Purple Ice slashes heat. Radiator Relief fights corrosion. Tomioka Racing RaceCool boosts performance. These picks tackle overheating, rust, and wear.
Easy to use. Works with all coolants. Saves money long-term.
Lowers temps by 15-30°F. Stops leaks. Extends engine life.
Trusted brands. For cars, trucks, or PCs. Perfect fit, every time.
List of Top 10 Coolant Additives
| Image | Title | Best For | Price |
|---|---|---|---|
 |
Royal Purple 01600 Purple Ice Super-Coolant Radiator Additive – 12 oz. |
This Royal Purple 01600 Purple Ice Super-Coolant Radiator Additive is perfect for anyone who wants to keep their vehicle’s engine cool and protected. It’s great for drivers who care about preventing damage and keeping their car running smoothly. |
|
 |
Design Engineering Radiator Relief Coolant Additive Engine Coolant for Cars, Trucks, RVs, Motorcycles & More Radiator Coolant Reduces Engine Temps Up to 30°F 16 oz. |
This coolant additive is perfect for anyone who wants to keep their vehicle running smoothly in hot weather. It’s great for cars, trucks, RVs, motorcycles, and more, helping prevent overheating and protect the engine. |
|
 |
Motorcraft VC8 Diesel engine coolant additive – 1 Pint(473 ml) |
Motorcraft VC8 Diesel Engine Coolant Additive is perfect for diesel vehicle owners who want to protect their engines and improve performance. It’s easy to use and works great for daily drivers and heavy-duty trucks. |
|
 |
RMI-25 Cooling System Treatment 8 ounce |
The RMI-25 Cooling System Treatment is perfect for anyone who wants to keep their vehicle’s cooling system in top shape. It’s easy to use and works as a cleaner, stabilizer, and leak detector all in one. |
|
 |
Tomioka Racing TR RaceCool High-Performance Coolant Additive – Lower Engine Temperature by 15°F, pH 10.5, Phosphate-Free, Low-Silicate, Ideal for Performance and Hot Rodding Engines 1Quart |
This coolant additive is perfect for car enthusiasts who want to keep their engines cool and running strong. It’s ideal for high-performance cars and hot rodding engines, offering reliable protection under extreme conditions. |
|
 |
WIX 24056 Radiator Liquid Cooling Treatment |
The WIX 24056 Radiator Liquid Cooling Treatment is perfect for car owners who want to keep their engines cool. It’s easy to use and works great for daily drivers or weekend adventurers. |
|
 |
Design Engineering 40208 Chill Charger Water-to-Air Intercooler Additive Engine Coolant for Auto Turbo and Supercharger Systems Lowers Intake Temperatures 16 oz |
Chill Charger is perfect for car lovers who want better engine performance. It’s great for turbo and supercharger systems, keeping temperatures low and engines running smoothly. |
|
 |
Design Engineering Radiator Relief Coolant Additive | Engine Coolant for Cars, Trucks, RVs, Motorcycles & More | Radiator Coolant Reduces Engine Temps Up to 30°F |32 oz. |
Radiator Relief is perfect for anyone who wants to keep their vehicle running cool and smooth. Whether you drive a car, truck, RV, or motorcycle, this coolant additive helps lower engine temperatures, prevents overheating, and protects your radiator. It’s easy to use and works with all types of engines and coolants. |
|
 |
Eastwood TIG Welder Torch Water Cooler Coolant Additive |
This coolant additive is perfect for TIG welders who want to keep their equipment running smoothly. It’s easy to use and saves money while preventing corrosion and freezing. |
|
 |
Mayhems – Water Cooling PC Coolant Additive – Inhibitor Plus – Prevents Metal Corrosion, 15 ml |
This coolant additive is perfect for PC enthusiasts who want to protect their water cooling systems. It’s ideal for anyone using Mayhems or other brands of coolant, ensuring longer-lasting performance and preventing corrosion. |
Detailed Reviews
Finding the perfect coolant additive can protect your engine and boost performance. Our expert-reviewed list of the top 10 coolant additives includes options that lower temps, prevent corrosion, and extend engine life—all tested for real-world results. Whether you drive a daily commuter or a high-performance machine, these picks deliver proven reliability and value to keep your engine cool under pressure.
1. Royal Purple 01600 Purple Ice Super-Coolant Radiator Additive – 12 oz.
The Royal Purple 01600 Purple Ice Super-Coolant keeps your engine safe. It protects the radiator and parts.
It prevents erosion and electrolysis. It works with all coolant types. It lubricates the water pump.
It is vehicle specific for a perfect fit. It helps your engine last longer. It keeps your car running cool.
| Pros | Cons |
|---|---|
|
|
Perfect For:
This Royal Purple 01600 Purple Ice Super-Coolant Radiator Additive is perfect for anyone who wants to keep their vehicle’s engine cool and protected. It’s great for drivers who care about preventing damage and keeping their car running smoothly.
Ready to Purchase?
2. Design Engineering Radiator Relief Coolant Additive Engine Coolant for Cars, Trucks, RVs, Motorcycles & More Radiator Coolant Reduces Engine Temps Up to 30°F 16 oz.
Radiator Relief is a powerful coolant additive that keeps your engine cool and efficient. It lowers engine temperatures by up to 30°F, helping your vehicle run smoothly in hot weather.
This additive prevents overheating and fights corrosion, keeping your engine in top shape. It also reduces scale buildup and protects your radiator core from damage.
Easy to use, safe for all vehicles, and compatible with any coolant. Just add 1 oz per quart for optimal results.
| Pros | Cons |
|---|---|
|
|
Perfect For:
This coolant additive is perfect for anyone who wants to keep their vehicle running smoothly in hot weather. It’s great for cars, trucks, RVs, motorcycles, and more, helping prevent overheating and protect the engine.
Ready to Purchase?
3. Motorcraft VC8 Diesel engine coolant additive – 1 Pint(473 ml)
Motorcraft VC8 is a diesel engine coolant additive. It comes in a 1-pint (473 ml) bottle.
This product is made by Motorcraft, a trusted brand. It’s designed for automotive use.
Easy to use, protects your engine, and improves performance.
| Pros | Cons |
|---|---|
|
|
Perfect For:
Motorcraft VC8 Diesel Engine Coolant Additive is perfect for diesel vehicle owners who want to protect their engines and improve performance. It’s easy to use and works great for daily drivers and heavy-duty trucks.
Ready to Purchase?
4. RMI-25 Cooling System Treatment 8 ounce
The RMI-25 Cooling System Treatment is a powerful 8-ounce solution for your vehicle’s cooling system. It keeps your engine running smoothly.
This treatment conditions, cleans, and protects your cooling system. It removes rust and scale, prevents leaks, and extends the life of your coolant.
With six key functions, it’s a must-have for car maintenance. It saves you time and money, keeps your engine cool, and ensures optimal performance.
| Pros | Cons |
|---|---|
|
|
Perfect For:
The RMI-25 Cooling System Treatment is perfect for anyone who wants to keep their vehicle’s cooling system in top shape. It’s easy to use and works as a cleaner, stabilizer, and leak detector all in one.
Ready to Purchase?
5. Tomioka Racing TR RaceCool High-Performance Coolant Additive – Lower Engine Temperature by 15°F, pH 10.5, Phosphate-Free, Low-Silicate, Ideal for Performance and Hot Rodding Engines 1Quart
Tomioka Racing TR RaceCool is a high-performance coolant additive made in the US. It lowers engine temperatures by up to 15°F, keeping your car running cool. This universal formula works for any car or model.
It’s easy to use—just add it to your coolant system. The phosphate-free, low-silicate formula protects your engine and extends its life.
| Pros | Cons |
|---|---|
|
|
Perfect For:
This coolant additive is perfect for car enthusiasts who want to keep their engines cool and running strong. It’s ideal for high-performance cars and hot rodding engines, offering reliable protection under extreme conditions.
Ready to Purchase?
6. WIX 24056 Radiator Liquid Cooling Treatment
WIX 24056 Radiator Liquid Cooling Treatment is an auto accessory. It helps your car’s cooling system work better.
This product keeps your radiator in good shape. It stops engines from overheat. It also fights corrosion and rust.
The item comes in one box. The box measures 13.23″ L x 8.74″ W x 6.71″ H. It weighs 69.99 lbs, so it’s easy to handle and store.
| Pros | Cons |
|---|---|
|
|
Perfect For:
The WIX 24056 Radiator Liquid Cooling Treatment is perfect for car owners who want to keep their engines cool. It’s easy to use and works great for daily drivers or weekend adventurers.
Ready to Purchase?
7. Design Engineering 40208 Chill Charger Water-to-Air Intercooler Additive Engine Coolant for Auto Turbo and Supercharger Systems Lowers Intake Temperatures 16 oz
Chill Charger boosts your engine’s cooling power. It lowers intake temperatures in turbo and supercharger systems, improving performance and reliability.
This coolant additive protects against corrosion and mineral build-up. It also reduces liquid heat soak, keeping your intercooler efficient during high-demand driving.
Use with any antifreeze. Mix with water. Store in a dry, ventilated area.
| Pros | Cons |
|---|---|
|
|
Perfect For:
Chill Charger is perfect for car lovers who want better engine performance. It’s great for turbo and supercharger systems, keeping temperatures low and engines running smoothly.
Ready to Purchase?
8. Design Engineering Radiator Relief Coolant Additive | Engine Coolant for Cars, Trucks, RVs, Motorcycles & More | Radiator Coolant Reduces Engine Temps Up to 30°F |32 oz.
Radiator Relief is a powerful coolant additive that keeps your engine cool and efficient. It lowers engine temperatures by up to 30°F, helping your vehicle run smoothly in hot weather.
It prevents overheating, stops corrosion, and protects your radiator. This additive also reduces mineral buildup, keeping your engine in top shape.
Safe and easy to use, it works with all coolant types and radiator materials. Just add 1 oz per quart for optimal results in cars, trucks, RVs, and more.
| Pros | Cons |
|---|---|
|
|
Perfect For:
Radiator Relief is perfect for anyone who wants to keep their vehicle running cool and smooth. Whether you drive a car, truck, RV, or motorcycle, this coolant additive helps lower engine temperatures, prevents overheating, and protects your radiator. It’s easy to use and works with all types of engines and coolants.
Ready to Purchase?
9. Eastwood TIG Welder Torch Water Cooler Coolant Additive
Keep your Eastwood TIG Welder Torch Water Cooler running at its best. This special coolant additive is designed for optimal performance and longevity.
It’s a non-hazardous formula. It prevents rust and freezing. This concentrated coolant saves you money.
Just mix 10 parts water to 1 part coolant. A quart bottle makes 2.5 gallons of powerful coolant. Keep your TIG cool for peak results.
| Pros | Cons |
|---|---|
|
|
Perfect For:
This coolant additive is perfect for TIG welders who want to keep their equipment running smoothly. It’s easy to use and saves money while preventing corrosion and freezing.
Ready to Purchase?
10. Mayhems – Water Cooling PC Coolant Additive – Inhibitor Plus – Prevents Metal Corrosion, 15 ml
Keep your PC cool and protected with Mayhems Inhibitor Plus. This essential additive is a must-have for any PC cooling setup. It offers top-tier performance to keep your system running smoothly.
Say goodbye to metal corrosion with this advanced formula. It safeguards your radiators and other metal parts.
Extend your coolant’s life and performance. It works with all Mayhems coolants and most other brands, ensuring broad compatibility.
| Pros | Cons |
|---|---|
|
|
Perfect For:
This coolant additive is perfect for PC enthusiasts who want to protect their water cooling systems. It’s ideal for anyone using Mayhems or other brands of coolant, ensuring longer-lasting performance and preventing corrosion.
Ready to Purchase?
Buying Guide
Coolant additives keep your engine cool, protected, and running longer. They fight overheating, rust, and wear. Pick the right one to save money and extend your vehicle’s life.
Factors to Consider When Buying Coolant Additives:
– Compatibility: Ensure the additive works with your coolant type and vehicle. Most are universal, but check for specific needs.
– Temperature Reduction: Look for additives that lower engine temps by 15-30°F. This keeps your car cool in hot weather.
– Corrosion Protection: Choose additives that fight rust and scale buildup. They protect your radiator and engine parts.
– Ease of Use: Pick products that are easy to mix and require no special tools. Follow the instructions for best results.
– Longevity: Opt for additives that extend coolant life and reduce maintenance. This saves time and money.
– Brand Reputation: Trust well-known brands like Royal Purple, Design Engineering, and Tomioka Racing. They offer reliable performance.
– Specific Needs: Consider your vehicle type (car, truck, PC) and driving conditions. Some additives are vehicle-specific for better results.
Engaging Experience:
Coolant additives are like engine heroes. They work quietly but make a big difference. Imagine driving on a hot day with no worries about overheating. Your engine stays cool, and you save on repairs. It’s a small investment for big peace of mind.