Top 5 Best Coolant Additive – Pick Efficient One Now!

by Mike Constanza

Coolants keep engines from overheating. It protects your vehicle from extreme temperatures and helps you evade unnecessary car repair expenses. Car engines may freeze during the winter and subsequently crack. It can keep your car from freezing up.

Engine coolant, also known as antifreeze, will not solidify even if the temperature is sub-zero. An engine coolant's basic ingredients include ethylene or propylene glycol and water. Thus, the best coolant additives prevent engine parts from corroding.

Likewise, running car engines can get hot enough to damage other vital parts of the vehicle. A coolant helps absorb the heat and dissipate it back through the radiator. It can protect your car engine from serious harm.

Summary Table for Top Coolant Additive

Image Product Name Price

Red Line (80204) Water Wetter Coolant Additives

Red Line (80204) Water Wetter Coolant Additives

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Royal Purple ROY01600 Purple Ice Super Coolant

Royal Purple ROY01600 Purple Ice Super Coolant

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 Genuine Ford Fluid VC-8 Diesel Cooling System Additive

Genuine Ford Fluid VC-8 Diesel Cooling System Additive

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Mishimoto Liquid Chill Radiator Coolant Additive

Mishimoto Liquid Chill Radiator Coolant Additive

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Baldwin CS5008 BTE Liquid Coolant Additive

Baldwin CS5008 BTE Liquid Coolant Additive

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5 Best Coolant Additive Reviews

5 Best Coolant Additive Reviews
5 Best Coolant Additive Reviews

Supplemental Coolant Additives or SCAs are chemicals added to an engine coolant to reinforce its anti-corrosive and other protective features. Here are the five best products from which you can choose.

1. Red Line (80204) Water Wetter Coolant Additives

Red Line (80204) Water Wetter Coolant Additives
Red Line (80204) Water Wetter Coolant Additives

This coolant additive has a unique ingredient that can keep the engine temperature low. It eradicates vapor barriers that form on hot metal surfaces, thus preventing the buildup of bubbles. The coolant additives protect your engine from rust and corrosion.

Therefore, you can use a minimal amount of antifreeze or straight water if you are in areas with warm climates.

Using this additive could never be easier, with each bottle being enough for passenger cars and light trucks. You only need to open the radiator cap and pour it in with or without a funnel.

Moreover, it is compatible with new or used antifreeze to help improve the heat transfer of ethylene and propylene glycol systems.

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Highlighted Features

  • Doubles the wetting ability of water
  • Improves heat transfer for maximum engine cooling
  • Lessens cylinder head temperatures
  • Reduces rust, scale, corrosion, and electrolysis of metals
  • Offers long-term protection against corrosion
  • Prevents foaming
  • Lubricates and cleans water pump seals

2. Royal Purple ROY01600 Purple Ice Super Coolant

Royal Purple ROY01600 Purple Ice Super Coolant
Royal Purple ROY01600 Purple Ice Super Coolant

This super coolant is one of the safest products since it does not contain any glycol. Car owners may use it with water only or antifreeze. Even though it does not provide freeze protection, it is compatible with cooling system additives that slow down or completely stop leaks.

The good thing about this super coolant is that you can also use it in diesel engines. It helps improve heat transfer and reduces cavitation in this engine type. And since it is a high-performance radiator conditioner, it defends your engine from corrosion year-round.

Moreover, the coolant prevents overheating and can keep the system clean; thus, extending your water pump's service life.

This superior protection helps aluminum combat electrolysis and erosion.

You can use this product in all-terrain type and utility vehicles, off-road and street-sport motorcycles, street-cruiser and street-touring motorcycles, motor scooters, snowmobiles, and other marine personal crafts. For more amazing products like this, check out our guide to the top Oil for Duramax.

Highlighted Features

  • Superior aluminum protection to combat corrosion, erosion, and electrolysis
  • A corrosion inhibitor and wetting agent in one
  • Reduces the surface tension of radiator coolant to lower engine temperatures
  • Diminishes hotspots in the engine and cylinder heads to avoid engine failure
  • Prevents overheating and keeps the system clean for extended life of the water pump
  • Does not contain glycol; thus, safe and legal for use

3. Genuine Ford Fluid VC-8 Diesel Cooling System Additive

 Genuine Ford Fluid VC-8 Diesel Cooling System Additive
Genuine Ford Fluid VC-8 Diesel Cooling System Additive

This coolant additive replaces the fluorescent green-colored V119 premium coolant meeting Ford specification ESE-M97B44-A. It also substitutes the yellow-colored Motorcraft gold antifreeze meeting Ford specification WSS-M97B51-A1.

Therefore, this product is designed to replace additives used with phased-out coolants for specific Ford vehicles. It is now colored yellow to avoid engine coolant color change when mixing.

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Highlighted Features

  • Premium antifreeze compatible with Ford vehicles
  • Genuine OEM
  • Compatible with all heavy-duty, diesel engine cooling systems meeting specific Ford models

4. Mishimoto Liquid Chill Radiator Coolant Additive

Mishimoto Liquid Chill Radiator Coolant Additive
Mishimoto Liquid Chill Radiator Coolant Additive

Being one of the best coolant additives, this product helps cool cars up to 30⁰ over regular coolant. It is compatible with all coolant and water mixtures.

This coolant additive is formulated to prevent corrosion and is 100% recyclable. It also helps reduce buildup while reducing high-coolant temperatures without the need for mixing.

Furthermore, this liquid is non-toxic and safe for use with alloys. As a bonus, it comes in a high-end packaging to protect the product and ensure that you get the high-quality coolant.

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Highlighted Features

  • Reduces existing buildup and prevents future corrosion
  • Decreases high temperatures of the coolant
  • Easy to use and does not need mixing
  • Compatible with all coolant and water mixtures
  • Non-Corrosive, non-toxic, 100% recyclable and biodegradable
  • High-End packaging for added product protection

5. Baldwin CS5008 BTE Liquid Coolant Additive

Baldwin CS5008 BTE Liquid Coolant Additive
Baldwin CS5008 BTE Liquid Coolant Additive

A highly durable product, this coolant additive provides superior protection against erosion and corrosion. It also reduces foaming, scaling, and cavitation. This additive also eradicates pump seepage due to the precipitation of granules on seals.

It is compatible with all ethylene glycol antifreeze containing sodium nitrite. However, you cannot use it with OAT-based coolants.

Highlighted Features

  • Superior protection against cavitation, erosion, and corrosion
  • Reduces foaming caused by coolant circulation
  • Eliminates pump seepage
  • Compatible with all ethylene glycol and heavy-duty antifreeze
  • Does not need initial treatment

Things to Consider Before Buying Coolant Additive

Best Coolant Additive
Best Coolant Additive

A useful coolant is one that can prevent your car from freezing, overheating, and corrosion. Additionally, it also helps improve the performance of your vehicle.

In choosing the perfect coolant additive, it is wise to consult with your car manufacturer's manual. It is to ensure that you get a suitable product for your specific car model. Below are the things you must look for in high-performing coolants.

Boiling and Freezing Points

The most effective engine coolant has a high boiling and lowest freezing points. It must be able to withstand a lot of heat and can remain stable even when the temperature reaches 200℉. Also, it must not build up ice on engines at temperatures of -20℉.

Further, radiator coolants will largely depend on your environment. Get a product with 70-30 or 60-40 antifreeze to distilled water ratio if you live in an area where temperatures can drop below 34℉.

Remember that the higher the antifreeze in the ratio, the lower the freezing point it can tolerate. But a 50-50 mixture can conduct heat more efficiently. Thus, it is safe in areas with temperatures down to -30℉.

Liquid Color

Coolants come in various colors to easily identify their chemical contents. Green coolants use Inorganic Acid Technology (IAT) and have silicates and phosphates to prevent corrosion.

Meanwhile, orange ones use Organic Acid Technology (OAT) with additives that act as corrosion inhibitors. This type lasts for about three years, longer than the green ones.

Corrosion Inhibitors

The brass, aluminum, and alloy parts of engines commonly corrode that may consequently reduce your car engine's life. Although water and ethylene or propylene glycol consist of the base of most coolants, additives that are corrosion inhibitors result in different types of coolants.

No one wants to use the wrong antifreeze in their engine. As mentioned, the ethylene glycol is an active ingredient used for engine coolant. It ensures that the liquid in your engine will not freeze and evaporate easily.

However, it can irritate your skin due to its high toxicity. Hence, it would be best if you observed extra care when using this antifreeze coolant.

Meanwhile, propylene glycol is thicker in texture and has more efficient heat transfer. Further, it is less toxic; thus, most car owners prefer this type of coolant.

Fuel Type and Engine Compatibility

You have to remember that diesel engines differ from engines using gasoline. Hence, these two fuel types will require different antifreeze specifications.

Diesel engines are more likely to have cylinder wall corrosion. It would be best if you refilled its radiators with antifreeze containing Supplemental Coolant Additives or SCA to avoid damages.

Its engines easily overheat; therefore, it is necessary to use antifreeze with a high boiling point. Nevertheless, it is prudent to always check the car's manual to be sure you are using the appropriate product.


Most engine coolants are made with 50% water, while some are already pre-diluted. Some car owners choose these ready-to-use diluted brands without the need to add water. Meanwhile, others prefer the DIY method of mixing water and antifreeze.

Just always read the label before mixing water with antifreeze to get the right proportion. Also, do not use non-distilled water since its mineral content can cause rusting and corrosion faster.

FAQs : Frequently Asked Questions & Answers

FAQs : Frequently Asked Questions & Answers
FAQs : Frequently Asked Questions & Answers

You can save money if you know how to maintain your car correctly. Also, you can do the simple tasks on your own like changing car fluids and coolant. Below are some questions you might ask when it comes to antifreeze.

1. Why do I need an engine coolant?

Coolants help prevent engines from overheating during hot weather and freezing when it is zero degrees Celsius (32°F) outside. Cars need coolant for the engine to run safely and efficiently. It circulates through the car engine and radiator to maintain its temperature in extreme weather conditions.

A regular engine flush is essential to avoid damages on a vehicle's cooling system. It includes your car radiator, water pump, and pipes. However, it would help if you also choose the proper coolant for your car when it is time for its scheduled engine flushing.

2. What is the best engine coolant?

Getting the greatest coolant will always depend on the vehicle's type, age, model, and manufacturer. If you know the year, make, and model, it will be easier for you to select the most appropriate engine coolant.

Note that using the wrong product may cause poor car performance and engine failure. A simple tip, car coolants come in different colors to easily identify their car compatibility. The IAT coolant usually is green in color, while the Hybrid Organic Acid Technology or HOAT comes in turquoise.

However, these colors may be different for other brands, especially if they come from other countries. Hence, color may not always be the perfect indicator when choosing the right coolant. It is always prudent to read the bottle label to ensure the compatibility of the coolant with your car.

Finally, your car manufacturer's manual is the best source of information. Always refer to it when choosing the most appropriate coolant for your vehicle. If you don't have a copy, it is most probably available on the manufacturer's website.

3. Should I add water with coolant?

You can use some coolants as it is without adding water or any additive. However, certain types that need 50% water mix. Always get the precise ratio when using antifreeze and additives in your car engine.

You do not want to create a coolant that is too weak or too strong to affect your car's performance. It all boils down to the car make and type that you own. And, always read the label to make sure if you need to mix it with water.

4. Can I use water in place of a coolant?

Most people ask why not use water, which is the most natural liquid coolant. The answer is simple. Water freezes at 32°F and boils at 212°F or 100°C. Thus, it is more likely that your engine will freeze in the winter and overheat during the hot summer.

Moreover, water causes metals to rust quickly. It will lead to scale buildup, clogging of your engine, and eventually ruining the car system. Water moisture also accelerates corrosion of radiators and cylinder heads made of aluminum.

Therefore, you still need to add corrosion inhibitors with water to cool your engine.

Using high-quality antifreeze and coolant can protect your vehicle from freezing, overheating, and corrosion. Extreme heat causes engine metal parts to expand and probably touch each other, causing them to wear easily.

A good coolant additive can reduce the temperature on engines and increase resistance against corrosion. It can help reduce surface tension and absorb and transfer heat from the engine more efficiently. Thus, providing your car to achieve maximum performance.

But here's a quick tip in case you get caught in an emergency where your car coolant reaches bottom low. You can use water to help you get to the nearest gas station or auto shop and immediately receive necessary car maintenance.

5. What is the difference between IAT, OAT, and HOAT?

There are various types of coolants for different kinds of vehicles. It includes the Inorganic Additive Technology (IAT), Organic Acid Technology (OAT), and Hybrid Organic Acid Technology (HOAT).

It would be best if you always used the type recommended for your vehicle. Below are the detailed features of each type.

6. Inorganic Additive Technology (IAT)

This coolant is made with ethylene glycol and is colored green. It has added silicates and phosphates to prevent corrosion. This type of coolant is typically used in older vehicles. Hence, it is not advisable for use in newer car engines. Car owners must replace IAT coolants every two years or every 24,000 miles.

7. Organic Acid Technology (OAT)

OAT engine coolant has a base made with propylene glycol and is typically orange in color. However, it can also come in different colors like dark green. Thus, it is wise always to check the label to avoid accidentally getting an incorrect coolant type.

OAT coolant is perfect for newer cars, especially those made from the year 2000 and above. It uses organic acid as a corrosion inhibitor. Additionally, OAT coolants can have additional additives to protect car engines. You must replace the OAT coolant type every five years or every 50,000 miles.

8. Hybrid Organic Acid Technology (HOAT)

HOAT, which is traditionally colored yellow, has become available in a wide array of colors like blue, orange, pink, and green. HOAT coolants have subcategories, including phosphate, silicate, and phosphate-free.

So, you must look at the brand name and label instead of just the color. It is to ensure that you are getting the right HOAT coolant.

Its formulation is the combination of OAT and IAT components. It uses silicates and organic acid to fight against engine corrosion. Like OAT coolants, you should replace your car HOAT product every five years or every 50,000 miles.

Final Words

Looking for the best coolant additive for your vehicle need not be complicated. Always use the one recommended only for your car engine. It would help if you refer to the manual or ask your car manufacturer to ensure that you are using the right product.

About Mike Constanza

For years, Mike had always told everyone "no other sport like baseball." True to his word, he keeps diligently collecting baseball-related stuff: cards, hats, jerseys, photos, signatures, hangers, shorts (you name it); especially anything related to the legendary player Jim Bouton.

Mike honorably received Bachelor of Science degree in Business Administration from University of Phoenix. In his graduation speech, he went on and on about baseball... until his best friend, James, signaled him to shut it.

He then worked for a domain registrar in Phoenix, AZ; speciallizng in auction services. One day at work, he saw the site pop on the for-sale list. Mike held his breath until decided to blow all of his savings for it.

Here we are; the site is where Mike expresses passion to the world. And certainly, he would try diversing it to various areas rather than just baseball.

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