Best Antifreeze: Keep Your Engine Cooler for Longer
Improve your engine’s performance with our top picks for the best antifreeze coolants
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PUBLISHED ON April 5, 2019
Antifreeze is the liquid that saves your engine from overheating in high and low temperatures. Antifreeze liquid typically comes as a mixture of water and glycol chemicals that act as lubricants and anti-corrosion agents to keep your radiator in good condition. Read on for our breakdown of some of the best antifreeze the market has to offer.
- Best OverallEvans High-Performance Waterless Engine CoolantSummarySummaryA water-free coolant that prolongs engine life and reduces corrosion. It is a chemically-stable formula that reduces the strain on the vehicle's cooling system by eliminating coolant loss.ProsProsPrevents corrosion and electrolysis issues. Reduces engine maintenance costs. High boiling point. No vaporization issues.ConsConsExpensive. Lower cooling point than other high-performance coolants. It’s time-consuming to turn your coolant into a water-free system.
- Best ValueZerex Original Green AntifreezeSummarySummaryA green coolant made from a combination of inorganic acid and multiple additives that reduce corrosion and rust on critical engine components.ProsProsIt’s a high-quality ethylene glycol coolant. Features corrosion- and rust-fighting properties. Works on all types of vehicles. Low silica count.ConsConsRequires changing every two years. Increased risk of corrosion due to a short lifespan. Contains ethylene glycol, which is toxic to the environment.
- Honorable MentionStar Brite Star-Cool Premium Synthetic Engine CoolantSummarySummaryStar Brite is a high-performance antifreeze that regulates engine temperatures to improve horsepower. It features a PCT additive that keeps the engine cooler for longer than conventional oil.ProsProsKeeps the vehicle lubricated and running smoothly. Eco-friendly design. Meets OEM and ASTM standards and is, therefore, an authentic product.ConsConsExpensive product. Not suitable for BMW engines. Easily contaminated by foreign coolants.
Why Trust Us
All of our reviews are based on market research, expert input, and practical experience with each product we include. This way, we offer genuine, accurate guides to help you find the best picks.
Benefits of Antifreeze
- Temperature protection. Antifreeze liquids are better at dissipating heat than other coolants. They prevent cooling systems from overheating during extreme heat conditions and from freezing during the winter.
- Prevent rust and corrosion. Rust and scale deposits tend to build up over a vehicle’s cooling system over time. That can cause a system failure. While regular coolants flush away the rust and deposits, antifreeze coolants have additives that prevent rust and corrosion from occurring in the first place.
- Prevent engine failure. When an engine overheats, the oil in the system starts to thin. With time, the unlubricated metals could start hitting each other in the combustion process. This domino effect results in an engine failure that could have otherwise been prevented.
- Better than water. Antifreeze coolants were created to overcome the shortcomings of water as a coolant. Water has low boiling and freezing points and is, therefore, not a suitable coolant in places with extreme weather conditions. Most antifreeze liquids, on the other hand, stay neutral despite temperature changes to prevent the freezing or overheating of critical engine parts.
- Extend the life of engine components. Antifreeze liquids prevent electrolysis that leads to the erosion of metal components. It also extends the life of plastic and rubber components in the cooling system that often melts as the system overheats. This will also save you some costly repairs.
Types of Antifreeze
Universal Antifreeze Coolants
Universal coolants are also known as 50/50 premix coolants. This is because they contain 50 percent demineralized water. Therefore, there is no need to dilute the solution before use. Universal coolants have low silica content to protect delicate parts of the engine and the radiator from corrosion.
Organic antifreeze is manufactured using Organic Acid Technology (OAT). Phosphates and silicates are eliminated from the liquid body, and the liquid is further formulated with corrosion inhibitors to prevent rust. This type of antifreeze is available in dark green, orange, pink, blue, and red. The service distance of a typical organic coolant is 150,000 miles, after which it should be replaced.
Inorganic antifreeze is formulated using Inorganic Acid Technology (IAT), and it contains ethylene glycol. It also contains silicates and phosphates, which could cause corrosion if not flushed out after a service distance of 30,000 miles. Inorganic coolants are suitable for older cars made from the early 1920s to the late 1990s. It comes in either yellow or green.
Hybrid Organic Acid Technology (HOAT)
HOAT is an organic acid that includes silicates as additives. The silicates inhibit corrosion on the alloy parts of the engine. HOAT coolants have a service life of five years or 150,000 miles, after which they should be flushed out. This type of coolant is either yellow or orange.
Zerex is a brand that specializes in antifreeze and other car-care products. Zerex always has the best antifreeze ratings, which is why Valvoline acquired it in 1994. Valvoline is a worldwide supplier of premium brand motor oils, lubricants, and antifreeze coolants. It has over 150 years of experience in the automotive service industry and maintains Zerex Original Green Antifreeze as its best-selling product.
Evans holds the record as the best antifreeze brand since it’s the only manufacturer of waterless antifreeze coolants. OEMs and companies such as Rotax, Noble, Honda World MX Team, and Kubota use Evans coolants. One of its prime products is the Evans High-Performance Waterless Engine Coolant.
Star Brite is a leading manufacturer of car polishes, waxes, motor oils, fuel additives, and coolants, among other car-care products. Many of Star Brite’s products are eco-friendly and biodegradable. The company has a state-of-the-art manufacturing facility in Fort Lauderdale, Florida. One of Star Brite’s popular products is the Star Brite Star-Cool Premium Synthetic Engine Coolant.
Maxima Racing Oils is a manufacturer of high-performance oils, lubes, and coolants suitable for heavy-duty race cars. Their products aim to improve the performance of vehicles in high-stress situations. This road-racing brand has over 30 years of experience in the motorsport industry, and its headquarters are in Southern California. The Maxima Coolanol 50/50 Blend Coolant has a loyal following as it is a good ethylene glycol antifreeze for aluminum engines.
- Under $30: This category has inexpensive antifreeze versions that contain ethylene glycol. They are mostly inorganic coolants that are green in color. They offer resistance to corrosion. They, however, have a short service life of only two years.
- $35-$60: This price point features high-performance antifreeze coolants that are ethylene glycol-free. They contain additives like nitrates, silicates, and sulfites that prevent corrosion and seal up leakages. They have a long service life of at least five years.
- Over $65: This is the price range you should be looking at if you want to spend a few extra dollars on a premium antifreeze. Antifreeze in this category are formulated with rust and corrosion inhibitors, and they have high boiling and cooling points. They are also eco-friendly and have a service life of at least six years.
The best coolants have high boiling and freezing points. Antifreeze coolants need to withstand a lot of heat before breaking down their molecules and vaporizing. Typically, they should remain stable at temperatures of 200 degrees Fahrenheit. The coolant should also prevent engine ice, even at temperatures of -20 degrees Fahrenheit.
Antifreeze coolants come in different colors to show that the liquid is formulated in a chemically different manner. For instance, green represents coolants formulated using Inorganic Acid Technology and contain silicates and phosphates as the main corrosion inhibitors. Orange coolants are formulated using Organic Acid Technology and have additives that act as corrosion inhibitors. Orange coolants also last three years longer than green coolants.
Type of Additive
Most antifreeze coolants have additives that give extra properties to the lubricant to enhance its performance. A common additive is demineralized water that is formulated as a 50/50 mix. Ethylene glycol is also a popular additive, as it has a low freezing point and is cheap to produce. Silicates, phosphates, and propylene glycol are also non-toxic additives that prevent corrosion to the vehicle’s cooling system.
- Engine Compatibility: Diesel engines require different antifreeze properties from gasoline engines. Diesel engines experience cylinder wall corrosion and, therefore, need antifreeze with Supplement Cooler Additives (SCA) to prevent corrosion. Engines tend to overheat and need an antifreeze with a high boiling point.
- Anti-corrosion Properties: Corrosion can occur on brass, aluminum, or alloy parts of an engine. Coolant must be specifically tailored to prevent electrolysis and chemical reactions in the engine that could cause corrosion of the metal components and ultimately reduce engine life.
Best Antifreeze Reviews & Recommendations 2019
Best Overall: Evans High-Performance Waterless Engine Coolant
Evans High-Performance Coolant tops our list as the best antifreeze coolant due to its high performance as a water-free coolant. Eliminating water from its formulation makes the coolant more resistant to corrosion to give your engine a longer life. This antifreeze is a propylene glycol-based formula that is non-reactive and, therefore, doesn’t cause electrolysis or cavitation erosion issues. It is the best antifreeze for vehicles with overheating problems as it doesn’t create hot spots or engine knocks.
This engine coolant has a high boiling point of 375 degrees Fahrenheit, meaning it won’t vaporize or cause boil over problems at that temperature. In case temperatures exceed its boiling point, this coolant will vaporize at a low pressure to reduce coolant loss and minimize strain on the car’s cooling system. In addition, it remains stable and maintains its liquid state at temperatures as low as -40 degrees Fahrenheit.
This antifreeze is expensive, however, and you need to convert your vehicle to a water-free coolant system which could take a long time. You would have to buy a water-free prep fluid to flush out the water-based coolant from the system. The cooling point is also lower than other high-performance coolants. This antifreeze is suitable for LP, CNG, gasoline, and light-duty diesel engines.
Best Value: Zerex Original Green Antifreeze
The original Zerex coolant is a ready-to-use inorganic acid formula that can be used with all vehicles that are compatible with a glycol-based coolant. It features high ethylene glycol content for antifreeze and coolant protection and low silicate content to prevent corrosion and rust from your engine’s critical components. The formula comes pre-mixed with demineralized water that prevents the build-up of debris within the vehicle’s cooling systems.
The coolant maintains the engine efficiency at temperatures as low as -34 degrees Fahrenheit and as high as 250 degrees Fahrenheit. It is green in color and is, therefore, compatible with engines that use traditional yellow or green coolants. It also works best with older engines with metal parts. Overall, Zerex Green is the best green antifreeze that can be used for decades with frequent changes.
The main drawback of the Zerex Original is that prolonged use leads to the breakdown of its chemical formula. You, therefore, need to flush the fluid from the engine after at least two years and replace it with a new liquid. The short lifespan of the coolant also increases the risk of corrosion of critical engine components, especially when the two years are over. Zerex is the best coolant to use for engines with copper core radiators and a must-have for older American or European vehicle models.
Honorable Mention: Star Brite Star-Cool Premium Synthetic Engine Coolant
Star Brite is a synthetic coolant tailored to resist the breakdown of components over time. It is an eco-friendly product and is also safe for metal engines like iron, aluminum, and copper. Star Brite lowers operating temperatures in the engine faster than most coolants. The manufacturer includes a PSV additive in its formulation to regulate the engine temperature and seal pinhole leaks.
Star Brite is an OEM- and ASTM- approved the product and comes as a ready-to-use coolant. It does not contain any nitrate, borate, silicate, phosphate, or amine in its formulation. Moreover, the fact that it’s devoid of the aforementioned harsh compounds makes it safe for parts like seals, welds, and gaskets. Its sealing properties also make this antifreeze a great choice for preventing system failure.
The downside of this product is that it is more expensive than non-synthetic antifreeze. Moreover, its performance is limited with most BMW car models. BMW engines tend to overheat faster than other car models and need a BMW coolant with a higher boiling point than the Star Brite antifreeze. You cannot mix Star Brite with other antifreeze coolants, as it can be easily contaminated.
Tips & Advice for Antifreeze Coolants
- Follow the recommended mixing ratio by the antifreeze manufacturer. While most coolants are ready to use, some need to be diluted with water in a 50-50 ratio. If you upset the balance of water and the coolant, you may end up with a solution that is too weak or too strong.
- Do not mix different types of antifreeze coolants in your system unless your vehicle’s manufacturer approves it. It may lead to an engine misfire as the new coolant may either not be suitable for your engine type or it could be contaminated by the previous coolant. Flush out the first coolant before you pour in the new coolant.
- Most antifreeze products come in vibrant colors that can pose a safety issue if you have children. Extra care should be taken to prevent children from ingesting the coolant, as most antifreeze liquids contain ethylene glycol, which is a toxic substance.
Q: How do I know when to change my coolant?
A: Change your coolant the moment it no longer feels slimy or slippery. That is an indication that the molecules have broken down, and the coolant has lost its anti-corrosion power. Alternatively, you could follow the manufacturer’s recommendation on when to change the coolant.
Q: What happens if I mix coolants?
A: The worst-case scenario would be an engine misfire due to reduced corrosion inhibitors, as mixed coolants tend to lose their properties. For instance, a water-less coolant won’t perform as well when mixed with an ethylene glycol coolant. However, some certain types of coolants can be mixed if they contain the same ingredients. The downside is that the engine performance will be relatively low compared to when a pure coolant is used.
Q: Why do antifreeze coolants come in different colors?
A: Color-coding is a method used by manufacturers to denote the manufacturing style of the coolant. Organic coolants are blue, dark green, or red. Inorganic coolants are green or yellow. HOAT is orange, blue, or yellow.
The best engine coolant that improves engine performance and has the best anti-rust and corrosion protection is the Evans High-Performance Waterless Engine Coolant.
Get the Zerex Original Green Antifreeze if you are on a budget.