Chill Out With Our Guide to Engine Coolant

A jug of bright pink liquid might not seem like an important part of the internal combustion process, but a bone-dry coolant tank could cause your vehicles to overheat and risk catastrophic damage in as little as five minutes. Aside from motor oil, coolant might be one of the most crucial fluids in any modern engine, thanks to its ability to shield the engine from extreme temperatures. What is it made of, how does it work, and can you reach for any old bottle when it comes time to top off the coolant reservoir or perform a full flush? We’ll answer all of those questions, discuss the role that coolant plays in newer hybrid and EV models, and share some red flags that could help you avoid having to make an appointment for car radiator repair near Lawrenceville as we explore the finer points of engine coolant.

What Is Coolant?

Coolant is composed of a mix of antifreeze (ethylene glycol) and water. It circulates through the engine to transfer heat into the radiators, where it’s effectively dispersed by the influx of cool air through the front grille. Once the coolant has had a little time to chill out, it’s sent right back to the engine, where it absorbs more heat and repeats the cycle until you finally put the vehicle in park and switch off the ignition. Coolant also raises the boiling point of water by around 10°F, which means it can withstand the higher temperatures of a Lawrenceville summer without boiling off in the form of steam.

Many drivers tend to think of coolant in terms of its heat-sinking properties, but it also plays a crucial role in cold weather. Antifreeze lowers the freezing point of the water in the coolant. This prevents the formation of ice that could damage crucial engine components, and also prevents the coolant from freezing solid in extremely cold weather. The approach works incredibly well, allowing vehicles to operate effectively in temperatures as low as -32°F. Coolant doesn’t just protect the engine from extreme high and low temperatures. It also contains additives that protect metal components from rust and corrosion.

It’s important to note that vehicles are not designed to run on pure antifreeze. Many brands offer pre-mixed 50% water, 50% ethylene glycol products that can be added directly to the coolant tank. It’s essential to verify that you are adding the correct product. Failing to dilute concentrated coolant properly will cause the fluid to lose many of its heat-fighting properties and can also lead to corrosion and potential engine failure. You’ll also want to combine unmixed antifreeze with distilled water, rather than regular tap water, which is often contaminated with minerals and other impurities that can cause scaling, corrosion, and even blockages in the radiators and cooling system.

Which Coolant Should You Use?

The one-size-fits-all solution is often tempting from a simplicity standpoint, but such shortcuts can lead to unintended consequences. While several brands offer so-called “universal” coolants designed to work in all makes and models, specific blends are usually better suited to ensure consistent, long-term performance. Most coolants offer similar heat- and cold-fighting properties, but the difference all comes down to the precise blend of additives.

These additive blends can typically be categorized into three main types: Inorganic Additive Technology (IAT), Organic Acid Technology (OAT), and Hybrid Organic Acid Technology (HOAT). IAT primarily employs silicones and phosphates to protect against corrosion. Although it represents the oldest formula, it has been quickly supplanted by newer OAT formulas. OAT coolant can be found in many of the market’s most popular vehicles, including all modern GM passenger cars and light trucks. Unlike IAT, it isn’t formulated with phosphates. OAT also lacks nitrates and silicates, which can be a significant factor in combating pesky deposits.

Finally, there’s HOAT coolant, which is the go-to choice for major European and Japanese automakers, as well as Ford. HOAT coolant combines the best aspects of the IAT and OAT approaches, although there can be a significant difference between specific HOAT products. For example, many Japanese brands use a specific HOAT formula known as P-HOAT (phosphate-based HOAT), which is designed without silicates to better protect crucial aluminum components.

While some drivers believe that a coolant can be distinguished by its color, this approach is actually a little outdated. It’s true that IAT tends to be green while OAT and HOAT products are usually a brighter orange, red, or yellow hue, but this color-coded system is certainly not universal. Ultimately, the only way to ensure you’re choosing the right coolant for your car, truck, or SUV is a little research. Your vehicle’s owner’s manual should clearly state the specific coolant that should be used to keep you chugging along, and most bottles will be clearly labeled by auto brand at your local parts store.

EVs and Hybrids

Coolant is an essential fluid for any vehicle that relies on an internal combustion engine (ICE), but it can also be found in many of today’s cutting-edge EVs. This specially formulated coolant serves a similar purpose to traditional coolant, but instead of keeping the engine within the right temperature range, it’s designed to keep the vehicle’s battery, electric motor, and inverter nice and cool. Instead of engine-powered pumps, EVs rely on electric pumps that circulate coolant through key components. While the chances of an overheated all-electric vehicle are relatively slim, it can still happen.

This specially formulated coolant serves a similar purpose to traditional coolant, and it isn’t drastically different from the formula you’d find in your typical gas-powered vehicle, with one important exception. EV coolant is usually non-conductive to reduce the likelihood of electrical shorts and fires, which means Lawrenceville drivers need to be extra careful before pulling the first bottle off the shelf at their local auto parts store.

What about hybrid vehicles that employ both gas engines and electric motors? Most hybrid models actually require two separate types of fluid: the typical engine coolant, designed to regulate the temperature of the internal combustion engine, and a special formula intended to keep the battery, electric motor, and inverter cool. The coolant used in hybrid and electric vehicles boasts a relatively long service life, lasting up to 10 years or 200,000 miles, depending on the model. As always, it’s essential to consult your owner’s manual, as different vehicles may have very different maintenance requirements.

Warning Signs and Timelines

There are a couple of key warning signs to watch for if you’re trying to help your vehicle stay cool. The first and most obvious sign would be steam emanating from underneath the hood or an overheated engine, which can be tracked right from your instrument cluster. Once the engine is warmed up, the engine temperature gauge should be right at the halfway mark. If it’s routinely creeping a little too far to the hotter side of the spectrum, it’s time to pop the hood and check your coolant reservoir. This white plastic tank is usually located right next to the radiator. It typically features integrated Min and Max marks that indicate the ideal coolant level when the engine is cold or warm.

Ideally, a vehicle should lose very little coolant during normal operation, approximately 1/4 cup per year. Conspicuously low coolant levels should be cause for concern, as they could indicate a major leak. Drivers should also keep an eye out for any drastic color changes, which could indicate that rust, oil, or other contaminants have entered the system. Leaking coolant will often produce a distinctive, sweet, syrupy smell when it comes into contact with the hotter components under the hood. A puddle of bright pink or green liquid in your driveway is another clear indication. A slow leak isn’t going to devastate the engine over the course of a single ride around Lawrenceville, but those who suspect that they’re dealing with a coolant-related issue should keep a close eye on the reservoir and promptly address any worsening symptoms before they can balloon into a major malfunction.

With a little knowledge and attention to detail, it’s relatively easy to keep your vehicle supplied with all the coolant it needs to provide safe, consistent service. Most experts recommend performing a full coolant flush every five years for newer vehicles. However, some older models that rely on IAT may require servicing every 30,000 miles. When it’s time to change your coolant, we recommend leaving the project to the professionals. While a thorough coolant flush can be performed at home by a reasonably skilled amateur mechanic, it’s always a good idea to play it safe when it comes to the primary system protecting your vehicle’s single-most expensive component from a trip to the junkyard. Air pockets and incomplete flushes can lead to engine damage that’ll cause you to lose your cool, and a whole bunch of cash, in the process.