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Understanding The Different Types Of Truck Coolant For Heavy Duty Vehicles

Essential heavy-duty truck coolant maintenance guide. Explore coolant types for engine protection and cost-effective maintenance.

Heavy-duty truck coolant maintenance is one of the most significant parts of fleet PM service, as it’s what stands between your fresh Cummins X15 running strong mile after mile and a blown engine requiring a complete rebuild or conversion. But choosing the right truck coolant for your fleet isn't easy — with so many different antifreeze coolant alternatives on the market, choosing the right one comes down to what fits best with your trucks.

In this comprehensive guide, we'll explore the four main types of diesel truck coolant and help you make an informed decision to keep your engines protected and your maintenance costs low.

What is Antifreeze Coolant (AFC)?

Antifreeze coolant, or coolant for short, is what essentially prevents your engine from overheating under normal circumstances or freezing at the lowest temperatures. It also provides protection against corrosion in the engine’s components, prevents erosion within the engine, lubricates coolant system components like the water pump, and allows your engine to transfer heat efficiently.

The Four Different Types of Truck Coolant

Coolant for diesel trucks generally comes in four different types: Inorganic Acid Technology, Organic Acid Technology, Hybrid Organic Acid Technology, and the most revolutionary of the bunch, Nitric Organic Acid Technology.

Inorganic Acid Technology (IAT)

If you've seen green or purple coolant in heavy-duty trucks, chances are it's Inorganic Acid Technology (IAT). IAT is one of the pioneers in truck coolant technology, and it is widely known for its low silicate-based formula. Despite their popularity in the 1990s, IATs aren't as common anymore since they can only be used effectively in older truck models with iron or copper parts. 

If you own an older truck model, IAT diesel truck coolant may be right for you. However, there's a catch — you'll need to add Supplemental Coolant Additives (SCAs) or extenders at the first 25,000-mile interval to protect your heavy-duty engine from corrosion. This can be a bit of a hassle and may raise maintenance costs, especially with their lower average lifespan compared to other alternatives. In short, IATs do the job but are not the most efficient option.

Hybrid Organic Acid Technology (HOAT)

Hybrid Organic Acid Technology coolants try to take the best of IAT and OAT inhibitors and merge them into one. They typically come in orange or yellow colors and, like IAT coolants, require SCAs to be added in the first 25,000-mile interval. While they offer some benefits from both IAT and OAT coolants, like the longer average service life found in OAT antifreeze coolants, the additional concentration testing and SCA requirements may not make them the most cost-effective choice for your diesel truck.

Nitric Organic Acid Technology (NOAT) or Extended Life Coolant (ELC)

Looking for a coolant that requires minimal chemical supplementation? NOATs, also known as Extended Life Coolants (ELCs), are designed to last for at least 300,000 miles or more without needing any additional chemicals. They use a combination of OAT corrosion inhibitors and nitrite to prevent corrosion and protect your cylinder liner.

ELCs are gaining popularity in the industry, as they can significantly reduce maintenance costs, improve water pump life, and eliminate the need for SCAs. Beware though — with NOATs, some engine manufacturers may recommend avoiding them, such as Detroit, due to the impact of nitrite on their engines’ aluminum parts. That’s why it’s important to factor in nitrite-free ELCs when purchasing truck coolant for a new engine.

Organic Acid Technology (OAT)

OAT coolants, commonly found in Europe and growing in popularity in North America, are a fantastic option if you want to reduce planned downtime and maintenance costs. They use a combination of organic acids and other inhibitor chemistries that remove the need for regular additions of SCAs. The heat transfer properties of OAT technology effectively target corrosion, making them an environmentally friendly option compared to IAT diesel truck coolants. What's more, OATs can last for an impressive 600,000 miles, providing long-lasting protection for your heavy-duty vehicles.

What Is the Best Diesel Truck Coolant?

Without a doubt, the best heavy-duty truck coolant for newer models is one that is nitrite-free. While nitrite is an excellent corrosion inhibitor, advancements in OAT formulas have diminished the need for it.

Nitrite-free coolants, such as OATs, nitrite-free ELCs or NOATs that control the nitrite reaction with aluminum, are the most cost-effective and efficient option. They offer extended service intervals of 500,000 to 1,000,000 miles or more without any additional maintenance.

The problem with IAT and HOAT formulas lies in their additional concentration testing, SCA requirements, and inapplicability to other manufacturing metals like iron or copper. The need for SCAs may raise maintenance costs and increase downtime, making them less appealing choices compared to OATs and ELCs.

How Long Does Coolant Last in a Truck

The lifespan of coolant for diesel trucks can vary depending on the technology you choose. ELCs and OATs have by far the longest service intervals, ranging from 500,000 to 1,000,000 miles or even more. This remarkable longevity can save you significant maintenance costs and keep your trucks on the road for extended periods without truck coolant changes.

How Many Gallons of Coolant Does a Semi-Truck Hold?

Semi-truck engines can typically hold anywhere from 7 to 14 gallons of coolant, depending on the engine's size. It's essential to know your truck's coolant capacity to ensure you have enough coolant to keep your engine adequately protected and running smoothly.

Final Words

Choosing the right coolant for your heavy-duty truck fleet is crucial for keeping your engines protected and your maintenance costs in check. Remember that the best antifreeze coolant for brand-new trucks is either nitrite-free or controls nitrite reactions with aluminum, offering extended service intervals and reducing the need for additional maintenance. 

Investing in the right truck coolant will not only extend the life of your heavy-duty vehicles but also contribute to smoother operations and reduced downtime. By understanding the different types of truck coolant available and their respective benefits, you'll be well-equipped to make an informed decision that suits your fleet's needs perfectly.

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