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Ask The NAPA Experts: What Is OAT Coolant?

Ask The NAPA Experts: What Is OAT Coolant?

OAT coolant isn’t exactly the kind of thing that gets discussed around the dinner table. That’s because engine coolant is designed to do its job quietly in the background with no drama. It isn’t an easy job transferring extreme heat from your engine to the radiator or heater core without going up in a steamy cloud. Most people don’t care that OAT coolant does so in an environmentally safe way or that it protects your engine from corrosion for a long service life. So, what is OAT coolant and what makes it different?

Let’s start by defining what exactly OAT coolant is in general terms. OAT stands for Organic Acid Technology, which refers to the recipe of chemicals used to formulate the coolant liquid itself. In this case, organic acids called carboxylates are used as corrosion inhibitors so that parts don’t rust from the inside-out. Modern OAT coolant does not use silicates or phosphates, which were commonly used in older coolant formulas. This allows for a longer service life for the coolant, sometimes well more than 100k miles depending on the situation.

What Color Is OAT Coolant?OAT coolant

In most cases, OAT coolant is an orange color, but that isn’t an absolute. There are additional colors on the market. For example, the factory MOPAR OAT coolant color is purple. You may also find pink, red or even dark-green OAT engine coolant. But, while you can use OAT coolant color as a quick visual sign of compatibility, just matching colors isn’t enough. You must always read the specifications on the coolant bottle to ensure it works with your vehicle. Your vehicle’s coolant specifications are available in your owner’s manual, usually toward the back. You do NOT want to accidentally mix two coolant types together in your cooling system, so make sure you are using the right specified coolant before topping off your radiator.

What Happens When You Mix OAT & HOAT Coolant?

If you accidentally mix OAT and HOAT coolant, you won’t see an instant dramatic event, but you will have contaminated your cooling system. That means the cooling liquid concoction that was accidentally created will not properly cool the engine as designed. Mixing coolant types can lead to overheating, corrosion and even water pump impeller damage as time passes. In extreme cases, the coolant mix can even turn into a thick gel that is useless for cooling an engine. If coolant does get mixed together, the proper solution is a cooling system flush. Draining the entire cooling system and refiling with the proper coolant type will guarantee your cooling system will do its job properly for a long time.

Where to Buy OAT Coolant?

If you are wondering where to buy OAT coolant, the answer is your local NAPA Auto Parts store. You can choose to buy OAT coolant in concentrated bottles or in 50/50 premixed, ready-to-use bottles. As mentioned previously, make sure to check your owner’s manual to pick the right compatible coolant. Your local NAPA Auto Care can also top off or even flush your cooling system with the correct OAT coolant your vehicle needs.

How Do You Use OAT Coolant?

OAT coolant is used like any other coolant. Make absolutely sure you know what kind of coolant is in your engine before adding any other coolant. Ideally, your engine is already filled with the type of coolant specified in your owner’s manual. If there is ever any doubt as to whether you accidentally mixing coolant types, it is worth your time to do a cooling system flush. 

Flushing your cooling system doesn’t take long and gives you peace of mind knowing that your coolant is fresh and ready for extreme temperatures. Always wait for the engine to cool before adding coolant. NEVER open a radiator cap or coolant overflow bottle while the engine is hot. When in doubt, wait an hour for the engine to cool completely. Use a funnel to prevent any spillage and fill the coolant bottle until it reaches the “Full” level mark. Check the coolant level after a few drives as air bubbles may get dislodged from the system, which means you need to add more coolant.

What about DEX-COOL?

You have probably heard stories about a certain OAT coolant named DEX-COOL. Back in the mid-1990s, General Motors decided it needed a better coolant, which was DEX-COOL. Starting with 1996 vehicles, GM started using DEX-COOL across its product lines. While there were some problems in the early rollout, modern DEX-COOL is perfectly fine and still in use by GM. DEX-COOL isn’t a bad coolant, it just has growing pains like any new product that makes a big change in an industry. Most vehicles that had issues using DEX-COOL were remedied long ago. So, if your Chevrolet Camaro or GMC Envoy says to use DEX-COOL, then that’s what you should use.

Trust Your Coolant to NAPA

If it’s time for a coolant flush or you just need a top-off, head over to your local NAPA Auto Parts store or shop NAPAonline for everything you need. Don’t feel like leaving the house or don’t have time? Select One-Day Shipping on more than 160,000 products. However you choose to shop, make sure to take advantage of NAPA Rewards. For every $1 you spend, you earn 1 Point. When you earn 100 Points, you get $5 off your next purchase automatically! 

Don’t feel like dealing with coolant yourself? Head on over to your local NAPA Auto Care. The ASE-trained technicians there have the expertise to inspect your cooling system and keep it in top condition. Plus, when you choose NAPA Auto Care, you are covered by our free 24-Month/24,000-Mile Peace of Mind Warranty, which spans across the entire nationwide NAPA Network and includes parts and labor on qualifying repairs and services.


Brian Medford View All

With an automotive writing career spanning over two decades, Brian has a passion for sharing the automotive lifestyle. An avid DIYer he can usually be found working on one of his many project cars. His current collection includes a 1969 Olds Delta 88 convertible, BMW E46 sedan, and a slant-6 powered 1975 Plymouth Duster.

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