Antifreeze & Coolant Protects Your Engine

David Hilgendorf

4 years ago

Antifreeze & coolant is critical to proper engine operation. Vehicle owners usually understand the importance of keeping their coolant reservoir full, but it’s often overlooked when performing preventative maintenance. One reason may be that they don’t realize the importance of a properly functioning cooling system for maximum engine performance. Another reason is the confusion surrounding the different “colors” of coolants on the market and potential problems when mixing incompatible coolants.

AMSOIL Tech Tips on Motorhead Garage with host John Gardner and AMSOIL product expert Len Groom: How to Check Your Engine’s Coolant System

Video transcript: How to Check Your Engine’s Coolant System

Featuring John Gardner, host of Motorhead Garage, and Leonard “Len” Groom, AMSOIL Director of Product Marketing (author profile).

John Gardner: We were rolling along on our way here to the shop, and look what we found. A vehicle broken down. Fortunately, we had our tools with us, so we went up under the hood and we found a coolant failure. One of the hoses actually blown off.

Welcome to this AMSOIL Tech Tip. Yeah. It’s all about the coolant system. And if we get into the coolant system, we have to look at how it functions.

And you can see here, it starts at the bottom there with the water pump. It’s gonna actually take the fluid up to the water pump through the block. Once it goes through the block, out a thermostat, and then returns back to the radiator. It’s all about that law of thermodynamics, and I have it for you right here.

You can actually see it. If I fire it up, I said it starts at the water pump, and then what’s happening here is it’s coming in through the bottom and out through a thermostat, which we don’t have on this motor, so it’s allowed to flow here and return to the radiator. I’m taking the heat from the motor, taking it to the outside air, boom, getting rid of it. Once again, that law of thermodynamics.

But you’re going to have to have a thermostat, and you can see a thermostat right there on this graphic. It’s actually open or closed. When it’s closed, it’s going to bypass and let the engine get up to temperature very quickly, kind of in emissions reasons. I got one right here and you can see it.

So when it opens and closes, hey, better yet, I can actually show it to you opening and closing. What we did is we took one of these thermostats and with temperature, we went ahead and boiled it. And once we boiled it, we got it above the temperature of where it needed to be open. You see the gap right there?

Well, that’s actually an open thermostat. So what do we do with it? Well, we put it in cold water. And once we put it in that cold water, you can actually see it start to close.

That’s pretty cool. Anytime you do any coolant repair, you want to have a thermostat. Now to check the coolant systems, you can do a couple things. Up on the screen, I got a refractometer.

You just look through it. You can see the glycol level. You can see if your coolant’s good. You can do test strips or you can do a hydrometer.

But Len, the deal is there’s all collage there of different color coolants. Manufacturers use specific coolant. That’s important with the vehicles today.

Len Groom: Right. There’s not just one or two types of coolant anymore. And the reason for the dye is to their specific type of coolant. But the reasoning behind that is the metals that we’re using to build the components, the engine block, the cylinder heads, the radiator aren’t just a couple different types of metal anymore. They’re aluminums. They’re alloys. There’s all different kinds and we need to be providing protection.

John Gardner: Now AMSOIL has that coolant for multiple engines?

Len Groom: That’s correct. We’ve got coolant for all your needs. Just got to look it up, what it fits, and go from there.

John Gardner: Now also tell me about this. This holds it looks pretty good, Len, but if you look inside, man, it’s totally rotted out and deteriorated. Right. Here’s a water pump right here. The fins are totally missing. That’s not going to produce any flow, man. Corrosion, big problem.

Len Groom: Right. Dissimilar metals, corrosion. It’s basically the coolant reacting with the engine block or the heads or the water pump, and that reaction creates corrosion. Metal can actually be stripped away.

John Gardner: Len, that’s incredible, and that’s why it’s so important to use AMSOIL coolant. You know, maintenance, maintenance, maintenance. You got it? Whether it’s your coolant system or any other system on your vehicle, AMSOIL has you covered. For a comprehensive and simple to use website, just go to AMSOIL.com.

Low-quality coolants can lead to cooling-system corrosion.

What is Antifreeze & Coolant?

Like motor oil, antifreeze & coolant consists of a base component mixed with additives. The base, either ethylene glycol (EG) or propylene glycol (PG), helps regulate engine temperature, lowering the freeze point of water to protect the engine during winter while raising the boiling point of water to help prevent engine overheating in the summer. It must first be mixed with distilled or high-purity water (usually 50/50), either by the antifreeze manufacturer or the consumer, before it goes into the vehicle’s radiator.

Ethylene Glycol is the more common of the two. Compared to PG at a similar mix ratio, it offers a slightly better freeze point and heat-transfer ability. Plus, it’s less expensive.
Propylene Glycol formulations are required by some racetracks and off-road parks.

Antifreeze & coolant must provide more than just freeze and boil protection. It also must guard against corrosion, cavitation, scaling and additive drop-out, and it’s up to the additives to achieve these tasks. There are three essential categories of additives, and any of them can be blended with the two glycols mentioned above.

Why Can’t I Just Use Water?

Because water boils at 212°F (100°C) and freezes at 32°F (0°C), it doesn’t have the temperature range to provide boil-over protection for normal engine operating temperatures or freeze protection fir normal winter temperatures.

However, mixing water 50/50 with antifreeze raises boil-over protection to around 265°F (129°C) and lowers freeze protection down to around -34°F (-37°C). Interestingly, the freeze point of straight antifreeze is only about 0°F (-18°C), underscoring the importance of mixing it with distilled or high-purity water.

Not only does antifreeze keep your engine’s temperature in check, it also provides the following benefits:

Protects against corrosion that damages metal components
Protects against scaling that interferes with heat transfer
Protects against cavitation and pitting that damages cylinder liners (heavy-duty applications)

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Additive Types

Inorganic salts, such as nitrites, phosphates and silicates, are used in the “green” conventional coolants traditionally found at most retailers due to their low price.
These additives work by forming a protective layer on metal cooling-system components, which helps prevent corrosion. Because these additives are depleted by forming a protective layer, conventional green coolants require regular changes, typically every two years.

Once depleted, these additives become the source of common cooling-system problems, like scale deposits. They can also be incompatible with each other, sometimes leading to drop-out in the form of an abrasive or slime. For these reasons, most manufacturers have moved away from inorganic salts.
Organic acids, often referred to as OATs (organic-acid technology) or POATs (poly-organic-acid technology), are much more robust and longer-lasting. Unlike organic acids that coat metal surfaces, organic acids provide corrosion protection by chemically interacting at the metallic corrosion sites.
They’re only used when needed, meaning they last much longer. They virtually eliminate drop-out, scaling and compatibility issues inherent to inorganic salts. This type of coolant can be used in a wide variety of applications, even mixing with other coolants as a top-off.
Hybrid-organic-acid technology, often called HOATs, is a combination of inorganic salts and organic acids. They work in tandem to minimize some of the issues with inorganic salts while relying on the organic acids to boost performance.

Incompatibility of Inorganic Salts

As mentioned, mixing coolant types that contain inorganic salts can alter the formulation enough to reduce protection. This can reduce the service life of both the coolant and the cooling-system components, leading to the following maintenance issues:

Corrosion of metals in the cooling system, which can lead to failure of the water pump, heater core, radiator and other components.
Scale deposits can form on metal parts, which reduces heat-transfer ability and contributes to overheating.
Additive drop-out, which can occur when incompatible inorganic salts are mixed. An abrasive or slime forms and is deposited throughout the cooling system, leading to poor performance and eventual failure.
Cavitation, or the erosion/corrosion of the cylinder liner, can occur if the coolant provides insufficient protection. Cavitation often results in internal coolant leaks, which can lead to engine failure.

Many of the issues outlined here can be resisted or prevented completely by using an antifreeze & coolant with organic-acid technology. While all coolants that pass relevant industry-standard testing provide a minimum level of protection, a properly formulated coolant using organic-acid technology provides the longest-lasting and best protection without the incompatibility issues that come with the inorganic salts found in “green” and hybrid coolants.

Water Quality is Critical

Low-quality or hard water is a leading cause of cooling-system problems. Minerals found in hard water, including magnesium and calcium, react with inorganic salts, like phosphates, found in conventional and hybrid coolants.

The byproducts form scale deposits on engine surfaces, reducing heat-transfer ability and contributing to damaging corrosion. For best performance, use only high-quality distilled water when mixing coolant. For maximum convenience, use a coolant pre-mixed with high-purity water.

AMSOIL Antifreeze & Coolant

AMSOIL offers four coolants, all of which offer a unique blend of organic acids. AMSOIL uses di-acid technology, which means both ends of the organic acid are active. This makes them work faster and form stronger bonds for enhanced protection.

Passenger Car & Light Truck Antifreeze & Coolant is formulated for all passenger vehicles. It is premixed 50/50 with high-quality water and ethylene glycol and compatible with all other antifreeze and coolant colors.

Heavy-Duty Antifreeze & Coolant is dialed in for the unique needs of on- and off-road heavy-duty applications. It is premixed 50/50 with high-quality water and ethylene glycol and compatible with all other antifreeze and coolant colors.

Propylene Glycol Antifreeze and Engine Coolant is a 100% propylene glycol formulation. It is a concentrate that requires mixing with distilled or high-quality water and is compatible with all other antifreeze and coolant colors.

Powersports Antifreeze & Coolant is an extended-life formula good for up to five years in hot-running, high-revving powersports applications. It is available by the quart premixed 50/50 with high-quality water and ethylene glycol. It is safe for copper, brass/bronze alloys and aluminum and is widely compatible with other coolants.

This article is part of our Battery and Cooling System Care guide. See every article in the guide.