10 Best Coolant Additives 2025 in the United States

The Zerex Asian Vehicle Red Silicate and Borate Free 50/50 Prediluted Ready-to-Use Antifreeze/Coolant is specifically formulated for Asian vehicles like Toyota, Lexus, and Scion, making it a good fit for owners of these cars. Its silicate and borate-free formula offers excellent corrosion protection and helps prevent scale and deposit build-up, which can be very beneficial for the long-term health of your car's cooling system.

Additionally, it meets several OEM and industry standards, ensuring its compatibility and reliability across various specifications. The product is designed for a long life, promising protection for up to 5 years or 150,000 miles, which means fewer changes and more convenience for the user. However, it's important to check your vehicle's specifications before purchasing to ensure full compatibility.

The ease of use is enhanced as it is prediluted and ready to use, eliminating the need for mixing. Despite its many advantages, buyers should be aware that it is tailored specifically for certain Asian vehicles, which might limit its universality. If you own one of the specified vehicles and want a reliable, long-lasting coolant, this product could be a very good choice.

The Zerex Valvoline DEX-Cool Organic Acid Technology Concentrate Antifreeze/Coolant is designed to deliver excellent freeze and anti-boil protection that surpasses standard industry requirements. Its formulation employs organic acid technology, which efficiently resists rust, scale, and corrosion, offering reliable protection for all cooling system metals, including aluminum. This ensures the longevity of your vehicle’s cooling system components.

The high-quality additives in this coolant also prevent leaks and are gentle on gaskets, hoses, plastics, and the vehicle's original finish, ensuring no unintended damage occurs with regular use. The product comes as an orange concentrate that needs to be mixed with water at specific ratios depending on the desired temperature range, providing flexibility in extreme temperature conditions from -84F to 270F.

The need to mix the concentrate with water might be seen as a minor inconvenience for some users who prefer a ready-to-use solution. This product is best suited for vehicle owners looking for robust protection and those who are comfortable with mixing concentrates. While it offers impressive protection and compatibility, it might not be as convenient for users preferring pre-mixed options.

The Zerex Dex-Cool Organic Acid Technology 50/50 Ready-to-Use Antifreeze/Coolant stands out with its impressive freeze protection and anti-boil performance, which surpasses industry standards. It employs organic acid technology to resist rust, scale, and corrosion, effectively protecting all cooling system metals, including aluminum.

This coolant additive is pre-mixed in a 50/50 ratio with deionized water, making it very convenient to use straight out of the bottle. Its temperature range is noteworthy, safeguarding engine components from winter freezing down to -34F and summer overheating up to 265F. The product is designed to be gentle on gaskets, hoses, plastics, and the original vehicle finish, reducing the risk of leaks and damage.

It features a five-year or 150,000-mile guarantee, offering peace of mind concerning engine protection from freeze-ups or boil-overs. Additionally, it includes a bittering agent (denatonium benzoate) to deter accidental ingestion, adding an extra layer of safety. It’s essential to ensure it is compatible with your vehicle’s specific coolant requirements since it is designed for modern engines. This product is particularly beneficial for those looking for a highly efficient and easy-to-use coolant additive that provides long-term protection and performance for their vehicles.