The Truth About Engine Coolant: Debunking Common Myths

Engine Coolant Myths Exposed: What Every Driver Needs to Know

Maintaining your vehicle’s engine coolant system is critical to preventing overheating, corrosion, and costly repairs. Too often, drivers confuse the terms antifreeze and coolant, or assume one product fits all applications. In reality, a high-quality engine coolant blend protects every component of your cooling system—water pump, radiator, cylinder head, and cylinder liners, core plugs, heater core, and the heater tubes that run to and from the heater core. By understanding exactly what goes into modern antifreeze, you can avoid expensive cooling system damage and keep your car running smoothly.

Cooling System Myth #1: You Can Use Plain Water Instead of Coolant

Reality: The experts say that water is the best coolant. That’s true as far as it goes; it does a better job of transferring heat than any automotive coolant. However, it doesn’t have any of the anti-corrosion,

Radiator corrosion caused by using water or worn-out coolant

anti-foaming, pH balancing, or water pump lubricants contained in real automotive coolant. Race cars use plain water to achieve maximum cooling. But they don’t worry much about corrosion because they drain the cooling system and rebuild the engine after every race.

You don’t do that with your family vehicle. So, while running plain water will keep your engine cool, it will also promote corrosion, causing your radiator, heater core, core plugs, and heater tubing to degrade and leak. The replacement cost of any of these components far exceeds the cost of using the recommended coolant in your engine.

Cooling system Myth #2: You can add a universal “all makes, all models” coolant to your cooling system because it says so on the bottle

Reality: Mixing different types of coolant can cause serious problems. The anti-corrosion additives in universal coolant can negatively react with the additives in your current coolant, not only canceling each other out but also accelerating corrosion. Mixing different coolants can also cause gelling that clogs the small passages in the heater core.

If a single coolant could actually work on all makes and all models, then carmakers have wasted decades of research trying to find just the proper coolant formula for their engines. When a company labels their coolant as “universal,” it means there’s nothing in the Universe it’s suitable for.

Cooling system Myth #3: Coolant lasts forever and never needs to be flushed

Reality: There’s some truth to the fact that the base chemical ethylene glycol in automotive coolant never wears out. However, there’s a catch: engine overheating degrades ethylene glycol, causing it to oxidize and break down. Overheated glycol loses its protection against freezing and boiling. Overheating aside, the additives in coolant DO wear out. Once the anti-corrosion additives in the coolant are depleted, galvanic action begins and you wind up with a system corrosion that damages your water pump, radiator, heater core, and tubing, core plugs, and cylinder liners.

Myth #4: The Thermostat Should Be Removed in Hot Weather to Help Cool Your Engine

Reality: Removing the thermostat can disrupt the engine’s ability to regulate temperature,

Engine Thermostat

potentially causing it to run too cool or too hot. The thermostat helps maintain the engine at an optimal temperature by controlling the flow of coolant. In addition, removing the thermostat can cause the engine to run below its optimal temperature, lowering gas mileage and causing carbon buildup in the cylinder.

Cooling system Myth #5: Freeze plugs protect your engine from freezing damage

First, the term “freeze plugs” is incorrect. They are actually called “core plugs,” and they exist for ONLY ONE REASON. Core plugs are used to plug holes in the engine that are created during the casting process. They’re used so the engine builder can remove the casting sand from the coolant passages. Once the casting sand is washed out, the engine builder installs core plugs to seal the cooling system.

If your coolant is too weak to withstand freezing, the engine block will likely crack long before the core plugs pop out. I’ve seen dozens of cracked blocks with the core plugs still in place. NEVER rely on a core plug to prevent engine freezing.

The Terms: What’s the Difference Between Anti-Freeze and Engine Coolant?

The terms coolant and antifreeze are often used interchangeably. But they’re not the same. In this article, we’ll delve into the differences between these two fluids and understand their significance in keeping our vehicles running smoothly.

Coolant and antifreeze are both fluids utilized in an automobile’s cooling system, but they serve different purposes.

Engfine Coolant

Coolant is a pre-mixed solution of 50:50 distilled or deionized water and concentrated antifreeze. The coolant and antifreeze mixture helps regulate the engine’s temperature by carrying away excess heat. In addition, the mixture lubricates the water pump and prevents cooling system corrosion.

Antifreeze

Antifreeze is a concentrate that must be mixed with de-ionized or distilled water before it can be added to the cooling system. It can’t be used in its concentrated form. Here’s why. Water is far more effective at removing heat from the engine than antifreeze alone. But using water in the engine facilitates galvanic action between dissimilar metals, causing corrosion to metal parts. Plus, plain water freezes in cold weather. Freezing can destroy the engine, and corrosion can cause leaks in the radiator and heater core, as well as reduce cooling. So, water should never be used without antifreeze.

What’s In Coolant?

Most coolant sold today is built with a base fluid of approximately 90%-95% ethylene glycol and 5% – 10% additives. Ethylene glycol provides a higher boiling point and a lower freezing point. So, offers more protection than plain water. Coolant also contains these additives:

Corrosion inhibitors

Borate— Lowers the freezing point. Increases the boiling point. Reduces friction. Prevents corrosion, especially at higher temperatures. Prolong the life of the coolant during storage. Coolants containing borate should never added to a cooling system that contains leftover green inorganic (IAT) coolant. Borate will reduce the life of IAT coolant.

Nitrite— Prevents corrosion on cast iron and steel components and reduces cavitation.  Coolants containing nitrite should never be added to a modern aluminum engine because it will damage the aluminum.

Phosphate— Phosphate is a fast-acting acid that forms a coating on metal parts to neutralize galvanic action. Some carmakers use it because it protects metal parts quickly. It works best on cast iron engines and components. However, it has a short lifespan and is prone to flaking off and forming scale, especially when mixed with hard water. Most European brands avoid phosphates.

Silicate— Silicate is a different type of fast-acting acid that quickly forms a barrier film coating on metal parts. It works well with aluminum components. However, silicate can be abrasive and can erode water pump seals and gaskets, and it has a short life.

• Sodium Benzoate— Assists in corrosion protection and prolongs the life of the coolant

• Organic Acid— Carboxylic Acid, 2-Ethylhexanoic Acid, and Succinic Acid. Organic acids work well with aluminum engines and hve a long lifespan.

Surfactants—  Surfactants reduce the surface tension of water to improve heat transfer.

• Anti-foaming Agents and pH Balancers

• Dyes 

©, 2018 Rick Muscoplat