Is All Antifreeze the Same? Everything You Need to Know About Types & Colors

Antifreeze is vital to vehicle maintenance, making sure engines operate efficiently in extreme temperatures while protecting key components from damage. Choosing a high-quality antifreeze prevents freezing, overheating, and corrosion over time—all of which can lead to costly repairs. Given recent advancements in automotive technology, not all antifreeze is the same—and selecting a reputable product compatible with your engine is more important than ever. Understanding the types of antifreeze and their applications will set you up for success.

Understanding the Primary Functions of Antifreeze

Antifreeze serves several vital functions in a vehicle’s cooling system, protecting the engine no matter the climate or weather conditions. Here’s a breakdown of how antifreeze works:

• Prevents Freezing: By lowering the freezing point of the coolant, antifreeze prevents water in the engine from freezing during low temperatures. This is especially important in colder climates, where frozen coolant can cause severe engine damage.
• Prevents Overheating: Antifreeze raises the boiling point of the coolant, allowing it to absorb and dissipate heat effectively. This keeps the engine from overheating, even under heavy workloads or high temperatures.
• Prevents Corrosion: Antifreeze contains additives designed to protect engine components from rust and corrosion. These inhibitors coat metal surfaces, ensuring the longevity of parts like radiators, water pumps, and engine blocks.

Is Coolant the Same as Antifreeze?

While the terms “coolant” and “antifreeze” are often used interchangeably, they are not identical. Antifreeze is a concentrated ethylene glycol or propylene glycol solution, while coolant is a mixture of antifreeze and water, usually in a 50/50 ratio. Coolant is what circulates through the engine’s cooling system, providing the benefits of antifreeze in a ready-to-use form.

Is All Antifreeze the Same?

No, not all antifreeze is the same. While the primary functions remain consistent, different types of antifreeze are designed for certain engine requirements or applications. Variations in chemical composition, performance, and compatibility make it critical to select the right antifreeze for a specific vehicle. A car’s make, model, and year—along with the type of engine components—are all factors that should influence your choice of antifreeze. Additionally, antifreeze products vary in lifespan, with some lasting significantly longer than others—reducing the frequency of required maintenance.

Exploring the Types of Antifreeze for Vehicles

There are four main types of antifreeze in the automotive and trucking industries. Over time, antifreeze formulations improved to provide greater protection and longer lifespans.

Inorganic Acid Technology (IAT)

You might know IAT as the traditional green coolant, once the preferred antifreeze solution for older vehicles. The silicates and phosphates in this antifreeze protect a vehicle’s cooling system from corrosion, especially in cast iron engine blocks.

Modern engines with aluminum and rubber components are less compatible with IAT antifreeze. The phosphates in IAT can dry out and cause harm to a vehicle’s rubber deals. Additionally, IAT’s silicates can cause scaling in vehicle systems with aluminum parts. Plus, IAT usually has to be replaced about every 200,000-250,000 miles, which is a shorter lifespan than other types of antifreeze. Without timely replacement, a vehicle could experience corrosion or electrolysis that lead to breakdowns.

Organic Acid Technology (OAT)

OAT antifreeze provides better performance for heavy-duty trucks and vehicles with rubber or aluminum parts, free of the silicates and phosphates in traditional IAT antifreeze. In fact, this type of antifreeze was developed to address problems with IAT. OATs are also free from nitrates, corrosion inhibitors that are sometimes included in antifreeze formulations designed for diesel engines. Nitrates can deplete over time due to high temperatures. Instead, OATs rely on other temperature-stable inhibitors to lessen corrosion and scaling that could lead to problems over time. Plus, OATs offer a longer lifespan than IATs, remaining effective for about 1,000,000 miles for heavy-duty diesel engines. 

OATs are an increasingly popular choice for diesel engine maintenance. When used for passenger cars, this type of antifreeze often comes in distinct colors based on makes and models. For example, Toyota Red and Subaru Blue can help vehicle owners and auto shop owners more easily identify which antifreeze they should use.

Nitrated Organic Acid Technology (NOAT)

Heavy-duty diesel engines endure significantly greater demands than passenger vehicles, often operating under extreme conditions and carrying heavier loads. This makes them more susceptible to issues like cavitation corrosion—a process where bubbles form and collapse on the cylinder liner surface. To ensure engine longevity and reliability, trucks need specialized protection to run smoothly. 

While OAT antifreeze is nitrate-free, NOAT antifreeze includes nitrates to assist with corrosion prevention. These nitrates are the main differentiator between NOAT and OAT formulations. Another key advantage of NOAT antifreeze is its extended service life. High-quality NOAT products can often provide effective protection for up to 1,200,000 miles before requiring replacement (for heavy-duty diesel engines), minimizing downtime and maintenance costs for fleet operators.

Hybrid Organic Acid Technology (HOAT)

Similar to NOAT, HOAT antifreeze offers impressive protection of vehicle components. Organic acids prevent corrosion and silicates safeguard aluminum parts, building on the learnings from IAT and OAT antifreezes. This formulation makes HOAT an optimal choice for mixed metal components, which are common in many modern-day vehicles. Similar to OAT and NOAT, this type of antifreeze does not require replacement until around 1,200,000 miles, offering an extended service life for heavy-duty diesel trucks. HOAT antifreeze can also come in specific colors from vehicle manufacturers.

Colored Antifreeze vs. Multi-vehicle Antifreeze: What’s the Difference?

Colored Antifreeze

Antifreeze can come in different colors to indicate its chemical composition and compatibility with specific vehicle makes and models. Purple, orange, gold, green, yellow, and other colors can help drivers quickly identify the right product for their cars. While the colors can be helpful, they can also be confusing—especially for auto shop owners managing multiple vehicles and looking for a quick solution.

Multi-vehicle Antifreeze

Multi-vehicle antifreeze, also referred to as universal or global antifreeze, provides a convenient alternative for automotive professionals seeking efficiency. These products are formulated to work across a wide range of vehicle types without compromising quality. These two standout HOAT options from Keller-Heartt Oil are both available in 55-gallon drums:

• ShellZone Multi-Vehicle Extended Life 50/50 Antifreeze & Summer Coolant: Engineered to perform across extreme temperatures (-34°F to +265°F with a 15-psi radiator cap), it guards against freezing, boil-over, and corrosion—including on aluminum components. Free from amines, borates, nitrites, and phosphates, this premium formula ensures up to five years or 150,000 miles of worry-free performance.
• TRUEGARD Global Antifreeze 100% Concentrate: This product provides year-round protection for automotive and light truck engines. In temperatures between -34°F to 265°F, it effectively safeguards components like aluminum, steel, and brass. Free from borax, nitrate, and amine, it’s an eco-friendly, reliable choice for various applications.

Is It OK to Mix Different Types of Antifreeze?

Mixing various types of antifreeze is not recommended and can cause serious issues. Incompatible formulas could lead to harmful reactions between them—reducing the performance of the antifreeze or even leading to scaling or gelling. For example, using IAT and OAT antifreezes together can cause blockages that overheat a vehicle’s engine. Likewise, mixing NOAT and OAT antifreezes can reduce their effectiveness. Always use a trustworthy multi-vehicle antifreeze or one specifically made for the vehicle.

How to Choose the Right Antifreeze for Your Needs

There are many types of antifreeze on the market—so how do you choose one? You should evaluate a product based on these considerations:

• Vehicle Make and Model: Consider using a reputable multi-vehicle antifreeze or follow specific manufacturer instructions for a colored option.
• Age of the Vehicle: Older cars may require IAT antifreeze, while newer models are often compatible with OAT or HOAT antifreezes—including multi-vehicle options.
• Performance and Longevity: Evaluate the lifespan and maintenance intervals of the antifreeze. Extended-life options can offer greater convenience for auto shop owners and customers alike.
• Brand Reputation: Trusted brands—such as ShellZone and TRUEGARD—are well-known for high-quality products that perform. You can feel confident knowing their formulations are expertly manufactured and thoroughly tested.

When Should You Replace a Vehicle’s Antifreeze?

Regular maintenance is essential to keeping a vehicle’s cooling system in optimal condition. Your antifreeze should come with recommendations for replacement. As mentioned before, extended-life products like ShellZone Multi-vehicle Antifreeze can last for 150,000 miles or five years prior to needing replacement.

If you notice these signs, it could be a sign of an underlying problem and likely indicates a need for antifreeze replacement:

• Coolant appears discolored, cloudy, or sludgy.
• Unusual engine overheating or warning lights.
• Leaks or a noticeable drop in coolant levels.

Reliable Antifreeze Products for Automotive Applications

Keller-Heartt Oil offers top-tier antifreeze products to meet your automotive needs. Whether you choose the ShellZone Multi-Vehicle Extended Life 50/50 Antifreeze & Summer Coolant, TRUEGARD Global Antifreeze, or another product, you can count on superior performance and protection. Our experts can also help you determine which types of antifreeze align with your applications. Visit our website to place your antifreeze order or contact us for additional business discounts.