Deep within your car, the engine is a place of controlled chaos, generating intense heat as it burns fuel to create power. Managing this heat is one of the most important jobs for maintaining a healthy and reliable vehicle. This is where engine coolant, often called antifreeze, comes in. This brightly colored liquid circulates through your engine and radiator, absorbing excess heat and preventing your engine from overheating in the summer and freezing in the winter. Using the wrong type of coolant or letting it run low can lead to catastrophic engine damage and expensive repairs. With so many different colors and types on the shelf, choosing the right one can feel confusing. This guide will explain the different types of engine coolants and recommend some top choices to ensure consistent performance and a long life for your car.

Understanding the Different Colors and Chemistries

The first thing you’ll notice about coolant is its color—green, orange, pink, blue, and yellow are all common. These colors aren't just for looks; they signify different chemical formulas designed for specific types of engines and cooling systems. Using the wrong one can cause corrosion and damage.

IAT (Inorganic Additive Technology)

This is the old-school, bright green coolant that was used in most cars built before the mid-1990s. IAT coolants use silicates and phosphates as corrosion inhibitors. They work well, but these additives deplete relatively quickly. Because of this, IAT coolants need to be changed more frequently, typically every two years or 30,000 miles. They are best suited for older, classic vehicles with copper and brass radiators.

OAT (Organic Acid Technology)

As engine materials evolved to include more aluminum and plastics, a new type of coolant was needed. OAT coolants were developed to meet this need. They are most often orange or red. Instead of silicates, they use organic acids as corrosion inhibitors. These additives last much longer, giving OAT coolants an extended service life, often up to five years or 150,000 miles. They are commonly specified for vehicles from General Motors (as Dex-Cool), Volkswagen, and some Asian manufacturers.

HOAT (Hybrid Organic Acid Technology)

HOAT coolants are, as the name suggests, a hybrid of IAT and OAT chemistries. They use organic acids but also add a small amount of silicates to provide fast-acting protection for a wider range of metals. This "best of both worlds" approach makes them very versatile. HOAT coolants come in various colors, including yellow, turquoise, and pink. They are used by many manufacturers, including Ford, Chrysler, and most European carmakers. Their service life is also long, typically five years or 150,000 miles.

The most important rule is to use the type of coolant specified in your vehicle's owner's manual. Mixing different types can cause the corrosion inhibitors to "fall out" of the solution, turning your coolant into a thick, damaging sludge.

Top Recommended Engine Coolants

With the chemistry understood, let's look at some of the best coolants on the market. These brands are known for their quality and for meeting the strict specifications of various automakers.

Zerex by Valvoline

Zerex is a highly respected name in the coolant world, and Valvoline offers a comprehensive lineup that covers almost every vehicle on the road. What makes Zerex a top recommendation is that they produce specific formulations designed to be direct replacements for OEM (Original Equipment Manufacturer) coolants.

  • Zerex Asian Vehicle Coolant: Available in red/pink or blue, this HOAT coolant is specifically formulated for Toyota, Lexus, Honda, Nissan, and other Asian makes. It is phosphate-enhanced and silicate-free, matching the factory-fill chemistry to prevent corrosion in aluminum engines.
  • Zerex G-05: This is a yellow HOAT coolant that is the factory-fill for many Ford, Chrysler, and Mercedes-Benz vehicles. It provides excellent protection for both older and newer cooling systems.
  • Zerex Dex-Cool: This is an orange OAT coolant licensed by GM for use in all of its vehicles that require Dex-Cool. It offers long-life protection for modern aluminum radiators.

By offering vehicle-specific formulas, Zerex takes the guesswork out of choosing the right product. You can be confident you are using a coolant that matches the precise needs of your car.

Prestone

Prestone is perhaps the most famous name in antifreeze, and their products are known for reliability and widespread availability. Their most popular product line is designed to be universally compatible, which can be a convenient choice for topping off your system or for use in multiple vehicles.

  • Prestone All Vehicles Coolant: This is their flagship product, a yellow coolant formulated with their "Cor-Guard" technology. Prestone states that this coolant is compatible with any color or type of coolant already in your system. This makes it a very convenient choice for a quick top-off without worrying about chemical reactions.
  • Benefits of Universal Coolant: For a complete flush and fill, many technicians still recommend a vehicle-specific coolant. But for topping off a low reservoir, a high-quality universal product like Prestone’s is a safe and reliable solution. It offers 10 years or 300,000 miles of protection when used in a full system flush.

PEAK

PEAK is another brand that offers both universal and OEM-specific coolants, giving consumers excellent choices at a competitive price point. Their products are trusted by professional mechanics and DIYers alike.

  • PEAK OET (Original Equipment Technology) Line: Similar to Zerex, PEAK offers a line of coolants specifically for North American, Asian, and European vehicles. Their color-coded bottles and clear labeling make it easy to find the exact formula your car requires.
  • PEAK Long Life Universal Coolant: This is their all-makes-and-models formula, providing long-lasting protection for any passenger car or light-duty truck. It's a great all-around product to have on hand in your garage.

PEAK’s commitment to providing both targeted and universal solutions makes them a strong competitor in the coolant market.