As car engines are improving with advanced fuel-saving technologies, vehicle cooling systems also improve to meet demanding specifications. Coolant formulas are evolving right along with automotive technology.
OAT (organic acid technology) is one of the modern coolants with extended life and efficient cooling system compatibility for the latest engines. However, there is confusion present among drivers about what is oat coolant and how it is different from traditional antifreeze.
I remember those times during my work at the workshop when the driver got confused by coolant colors and didn’t know much about acid technology and the pH of engine coolant.
In this article, we’ll explore what exactly OAT coolant is, how its formula differs with specialized additives, and where it provides advantages over standard ethylene glycol antifreeze.
We’ll start by explaining the purpose of OAT coolant and what makes its formula unique. You’ll also get insights into where OAT coolant is commonly used. We’ll examine its applications in hybrid vehicles and variations formulated for Asian and European cars.
In addition to the benefits, we’ll also cover some potential issues to be aware of, such as compatibility concerns when mixing brands. There are a few misconceptions about OAT coolant that we aim to clarify as well.
Let’s get started exploring the world of OAT coolant!
What is Oat Coolant?
OAT stands for “Organic Additive Technology”. OAT coolants are actually made for the modern engine technology and the advanced cooling systems used in modern cars because traditional ethylene glycol-based coolants were not able to provide adequate protection.
OAT coolants are formulated using new organic acid technology additive packages within their formula. These organically based additives increase their compatibility with modern cooling system materials like aluminum, plastics, and rubber.
They also improve characteristics like corrosion protection and lubricity within the coolant system.
Origin of OAT coolant
The first OAT coolants began emerging in the late 1990s as a solution for BMW and Mercedes engines that required stronger additive platforms. Their usage has expanded significantly as more automakers now specify OAT coolants as factory-fill for their latest engines.
Popular applications include hybrids, turbocharged direct-injected engines, and aluminum-block engines from Toyota, Volkswagen, Ford, and General Motors.
Purpose: What is oat coolant for?
OAT coolant serves the basic function of circulating through the engine to regulate operating temperature via heat absorption and transfer. However, OAT coolant was developed particularly for modern engine technologies.
Many new engines use lighter but more vulnerable materials like aluminum alloy in their construction. They also have very tight tolerances and employ techniques such as direct fuel injection and turbocharging which generate additional heat.
The specialized additive technology in OAT coolant allows it to meet demands that traditional ethylene glycol-based coolants could not. Its organically-fortified formula makes OAT coolant better suited for protecting modern engine alloys from corrosion.
The enhanced lubrication OAT coolant provides also helps precision components last longer. Its efficient heat transfer abilities preserve tight tolerances so engines can achieve their optimal power and efficiency levels over long operating periods.
In essence, OAT coolant was tailored to handle the elevated heat and material compatibility challenges presented by advanced new engine designs. Its high-performance abilities directly support technologies that have enabled leaps in automotive engineering.
Ingredients: What is in oat coolant?
OAT coolant contains ethylene glycol or propylene glycol as its base, but also includes specialized additive ingredients not found in conventional coolants:
- OAT Additives: These include various organic acids and synthesizers that form a strongly protective corrosion inhibitor layer. Their nanotechnology abilities allow the film to self-heal any damage.
- Silicate: Acting as both an anticorrosive and detergent, silicate rinses away engine deposits for continued heat transfer efficiency. It also protects water pumps from scale buildup.
- Nitrite: This additive reacts with metal surfaces to establish oxidation protection from rust and corrosion. It forms a barrier that safeguards aluminum and other alloys.
- Molybdate: This lubricity additive creates a slippery, non-stick surface inside the cooling system. It reduces friction for smooth water pump operation and minimizes overheating risks.
- Dyes/Tracers: OAT coolants often contain fluorescent or azo dyes to be visually identifiable. Tracer chemicals also aid leak detection under ultraviolet inspection.
By combining these specialized ingredients through proprietary organic acid technology, OAT coolant delivers enhanced performance benefits like extended component life, optimal heat transfer, and maximum system protection compared to conventional glycol-based antifreeze.
What color is oat coolant?
Oat (Organic Acid Technology) coolant typically comes in a distinctive red or pink color. This color helps differentiate it from other types of coolant, making it easily identifiable for use in specific vehicle applications. It’s important to note that the coolant color can vary slightly between manufacturers, but red or pink is a common identifier for oat coolants.
Many manufacturers also make yellow, blue, or dark green colored oat coolants but always check the formulation and ingredients before buying one.
Can Oat Coolant Be Green?
Oat coolant is typically not green in color. It’s commonly associated with a red or pink hue, which helps distinguish it from other types of coolants.
Benefits of Oat Coolant
Here are the key benefits of using OAT coolant:
Improved Compatibility
Its organically based formula makes it less corrosive to modern engine materials like aluminum, rubber, and plastics compared to traditional ethylene glycol. This prevents damage and leakage.
Enhanced Corrosion & Rust Protection
The organic acid technology additives in OAT coolant form a stronger protective film on metal surfaces to guard against corrosion. This preserves critical cooling system components.
Better Lubricity
The additive lubricants within OAT coolant lubricate water pumps and other coolant pumps for maximum lifespan. Regular coolants do not distribute lubrication as effectively.
Engine Performance Gains
OAT coolant can transfer heat more efficiently through engines for optimized temperature regulation. Close tolerances are maintained, maximizing power output and efficiency.
Extended Service Life
OAT coolant is more durable and resistant to breakdown over time due to heat, ensuring it circulates properly for 5 years/150,000 miles or more between changes. Regular coolant may start to fail earlier.
Compatibility with Hybrid Vehicles
Hybrids integrate both gasoline and electric power systems, facing unique thermal challenges. The ethylene glycol base of OAT coolant poses no risk to their high-voltage battery packs. Its balanced pH also avoids electrolysis issues seen with conventional coolants.
Advanced additives maintain temperatures safely within battery coolant loops. This ensures hybrids can realize their full driving range and service lifetimes.
Also Read: 6 Best Antifreeze for Older Cars
Types of oat coolant
Here are the main types of OAT coolant explained in more detail:
HOAT
Hybrid Organic Additive Technology coolants contain a mix of organic and inorganic inhibitors like silicates, nitrites, and phosphates. Used widely as a universal coolant for most gasoline/diesel vehicles in North America, Europe, and other regions from 1996 to the present.
N-HOAT or NOAT
It is also a hybrid technology. Nitrite-free varieties omit potentially harmful nitrites preferred by Japanese and some European automakers like Toyota, Honda, Nissan, Volkswagen, BMW, and Audi. Common in Japan, Eastern Asia, and Western Europe.
P-HOAT or POAT
That is also a hybrid technology but does not work in the regions having hard water. Phosphate-free versions are suited for some Porsche, VW, and Audi models sensitive to phosphates. Found more commonly in Germany and other parts of Western/Central Europe.
Si-HOAT or SOAT
These silicon hybrid technology-based coolants are very effective against corrosion but deplete very quickly. Removing silicates accommodates certain aluminum-block engines from Toyota, Honda, and other Asian automakers requiring strict silicate limits. Popular in Japan, Southeast Asia, Australia/New Zealand.
HOAT+
Extended life HOAT incorporates extra corrosion inhibitors for a no-drain interval of 6 years/150k miles. They are approved for most vehicles globally but gaining traction in North America where longer service intervals are valued.
OAT vs Conventional Coolants
Here are the main differences between OAT coolants and conventional ethylene glycol-based coolants:
| Coolant Type | OAT Coolant | Conventional Coolant |
| Chemistry | Proprietary organic acid technology (OAT) additives | Ethylene glycol base with inorganic additives like silicates, nitrites, phosphates |
| Compatibility | Less corrosive, and better suited for modern materials like aluminum | Can cause corrosion issues in some newer cooling system materials |
| Protection | Forms a very strong rust/corrosion inhibitor layer | Inhibitor layer is not as effective, more susceptible to degradation |
| Lubrication | Effective lubrication of water pumps and coolant pumps | Lubricity is not as optimized, more wear on components |
| Service Life | Resists chemical breakdown longer, 5+ years/150k+ miles | May start failing earlier due to the inability to withstand heat |
| Temperature Regulation | Transfers heat very efficiently for precise control | Not as optimized, wider operating temperature range |
| Approval | Recommended fill for many new engine designs | Becoming obsolete as technologies evolve |
What is HD Oat Coolant?
HD OAT (high-duty organic acid technology) coolant is a specialized type of OAT coolant formulated for the more demanding needs of heavy-duty diesel engines. Some key aspects:
Higher Temperature Resistance
- Diesel engines operate at higher compression ratios and temperatures than gas engines. HD OAT can withstand consistent temperatures of up to 280°F/138°C.
Superior Corrosion Protection
- Diesel engines have more stressed cooling systems with wider temperature fluctuations. HD OAT provides a maximum barrier against rust and corrosion to protect critical engine parts.
Extended Service Life
- Designed to last the duration between scheduled maintenance intervals, which can be as long as 12,000-24,000 miles for heavy-duty diesels.
Nitrite-Free Options
- Available without nitrites for applications sensitive to this additive, like newer low-emission diesel engines.
Commercial Vehicle Approval
- Meets all original equipment manufacturer (OEM) specifications for diesel trucks, buses, construction, and agricultural vehicles.
By specially fortifying its corrosion inhibitors and heat resistance, HD OAT coolant ensures diesel engines in demanding applications can thrive for many years of intensive use.
Application of heavy-duty OAT coolant
Heavy-duty oat coolant is used in trucks, heavy equipment, marine diesel engines, and other vehicles with large, high-output diesel powertrains.
It is also used in agricultural vehicles like Tractors, harvesting equipment, and other farm machinery that face dirt/dust conditions and engine loads that stress conventional coolants.
Problems with oat coolant
Besides the marvelous benefits of using oat coolants in modern cars like extended life and better cooling, there are problems that can occur with OAT coolants:
Compatibility issues
If the wrong type of OAT coolant is used, it can become incompatible with certain engine materials over time. This can cause clogging or corrosion in the cooling system.
High alkalinity
While the alkaline reserve acts as an acid buffer, the high pH level of some OAT coolants can attack rubber seals, gaskets, and hoses after prolonged use.
Drain/flush requirements
Switching between OAT coolant and conventional ethylene glycol-based coolant may require cooling system flushes, otherwise, the differing chemistries could mix and cause issues.
Leak detection difficulties
The dye indicators added to OAT coolants can fade faster than conventional types, making low-level leaks harder to spot using UV light inspection.
Vulnerability to variances
The actual protection lifespan may be shorter than rated if the coolant is not changed or flushed as frequently as recommended by the manufacturer.
Increased costs
OAT coolants generally have a higher price point than traditional ethylene glycol antifreeze, raising long-term vehicle maintenance expenses.
Environmental regulations
Spills and disposal of expired OAT coolant solution require more stringent handling versus conventional coolant due to toxicity.
Proper coolant flushes and timely replacements are needed to avoid these issues and maximize the intended performance benefits of OAT technology.
Identification of OAT Antifreeze
How to tell if coolant is OAT?
Identifying Organic Acid Technology (OAT) coolant can be done by examining its color and checking the label on the coolant container. Here are the steps to determine if a coolant is OAT:
- Check the Color: OAT coolants are typically red or pink. While the shade may vary slightly between manufacturers, this color is a key identifier for OAT coolants. If the coolant in your vehicle’s reservoir is red or pink, it’s a strong indication that it’s OAT coolant.
- Read the Label: Coolant containers often have labels that specify the type of coolant they contain. Look for phrases like “OAT,” “Organic Acid Technology,” or “Extended Life Coolant” on the label. These terms indicate that the coolant is OAT-based.
- Manufacturer Recommendations: The manufacturer of the coolant may also provide information on the label or their website about the coolant’s type.
- Seek Professional Advice: If you’re uncertain about the type of coolant in your vehicle, consider consulting a professional mechanic or an automotive service center. They can inspect the coolant and provide guidance based on your vehicle’s make and model.
What cars use oat coolant?
Here are some of the most common cars that use OAT coolant:
- Toyota – Most Toyota models since the late 1990s recommend OAT coolant.
- Honda – Honda started recommending OAT in the late 1990s. Civic, Accord, CR-V, Odyssey, etc. use it.
- Ford – Ford transitioned to OAT for most models in the early 2000s. F-Series trucks, Mustang, Escape use it.
- GM – GM began adopting OAT in the late 90s. Vehicles like Silverado, Tahoe, Equinox, and Camaro use OAT.
- Nissan – Nissan recommends OAT for many vehicles from the 2000s like Altima, Maxima, Pathfinder, and Frontier.
- Volkswagen – VW switched to OAT for Golf, Jetta, Passat, and Tiguan in the early 2000s.
- BMW – BMW recommends OAT for most 3-Series, 5-Series, X3, and X5 from the late 1990s.
- Mercedes-Benz – OAT has been recommended for E-Class, C-Class, and ML-Class since the late 1990s.
- Chrysler/Jeep – Brands moved to OAT specification in radiators and owner manuals from the late 90s.
How to Properly Add Oat Coolant to Engine
Here are the steps to properly add OAT coolant to your vehicle’s cooling system:
- Locate the coolant reservoir or expansion tank. It is usually found in the engine compartment.
- Check the owner’s manual for the specific coolant type and ratio recommended for your vehicle. Most require a 50/50 mix of coolant and distilled water.
- Make sure the engine is completely cool before opening any radiator or coolant system components.
- Check the fluid level in the reservoir and add premixed OAT coolant as needed, following the minimum/maximum level marks.
- With the engine off, start the vehicle and run the heat on high for 10-15 minutes. This will circulate coolant through the entire system.
- Check the fluid level again and add the coolant as the level drops during heat circulation.
- Once full, continue running the heat for an additional 5-10 minutes to purge any air bubbles present in the coolant.
- Top off one final time, then replace the reservoir cap securely.
- Check for coolant leaks over the next few days as the system pressurizes fully with the new coolant. Refill as needed.
Proper mixing ratio and bleeding air from the system are key to ensuring OAT coolant protects the engine as the manufacturer intended.
Oat coolant brands
Here are some popular brands of OAT (organic acid technology) coolant:
- Peak Global – Peak OAT coolant is widely available and OEM-approved for many vehicle makes and models.
- Prestone – Prestone’s Heavy Duty formulation is a top-selling brand at auto parts stores for domestic and import vehicles.
- Zerex – Part of the PETRO-CANADA line, Zerex OAT coolant is G05/S40 specification.
- Shell Rotella – Shell’s heavy-duty coolant line aims for diesel and commercial fleet applications.
- Valvoline – Valvoline’s MaxLife OAT coolant brand is available in many auto and parts retail locations.
Can Hoat And Oat Coolant Be Mixed?
No, you cannot mix Hoat and OAT as both have different chemistries.
You must be thinking that both are organic-based formulas so why mixing cannot be done? While both contain organic acid corrosion inhibitors, the precise chemical formulations differ between HOAT and OAT types.
Mixing the two coolants could potentially cause incompatibility issues like coolant gelation or sediment formation over time which reduces the overall protection of the cooling system.
Can You Mix Oat Coolant With Water?
Yes, you can mix OAT coolant with water. OAT coolant is formulated to be diluted with water during use in a vehicle’s cooling system. The recommended mixing ratio for OAT coolant is generally a 50/50 mix of coolant concentrate and distilled water.
Related Questions
Is Oat Coolant Ethylene Glycol?
Yes, OAT coolant is typically based on ethylene glycol, similar to traditional coolants. However, OAT coolant contains organic acids as additives that provide extended corrosion protection and improved longevity for modern engines.
Is Oat Coolant G12?
No, oat coolant is not g12 but they both share some characteristics but they are not identical. G12 is a specific type of coolant used by some car manufacturers, like Volkswagen and Audi, and is often dyed purple or pink.
Is Oat Coolant Silicate Free?
Yes, OAT coolant is typically silicate-free. One of the advantages of OAT coolant is that it uses organic acids and inhibitors instead of traditional silicates, which can provide improved corrosion protection and extended coolant life, especially for modern engines.
Is Oat Coolant Safe For Aluminum?
Yes, OAT coolant is generally safe for use with aluminum components in a vehicle’s cooling system. OAT coolant is formulated to be compatible with a wide range of materials, including aluminum, and it provides effective corrosion protection for these components.
Can I Use Oat Coolant Instead Of Hoat?
Using OAT instead of HOAT is generally not recommended. Mixing coolant types can affect the properties and performance of the coolant and may lead to cooling system issues.
Conclusion
OAT coolant provides several benefits for users seeking to properly maintain their vehicle’s cooling system. As a global extended-life coolant, OAT allows for longer service intervals before replacement is needed compared to traditional antifreeze. This saves users time and money over the life of their vehicle.
OAT represents an outstanding option for most cooling system needs by providing robust corrosion defense with minimal maintenance. Its universal compatibility with most vehicles also eliminates worries about using the wrong type of antifreeze.
Joseph Morgan has decades of automotive experience. The Detroit native started restoring classics in the 1970s. He owned a vintage repair shop and authored articles for car magazines. With a 1965 Mustang fastback of his own, Joseph now shares advice through his YouTube channel. From engine swaps to rust repair, his expertise helps preserve automotive history.