What's so cool about engine anti-freeze? An introduction to Coolant Technology.

What is Engine Coolant and What Does It Do?

An engine coolant is a fluid designed to remove excess heat from an internal combustion engine by transfering it to the liquid. It also serves to prevent freezing and most importantly protection from corrosion. An operating engine typically only converts 1/3 of the energy created through the combustion of fuel into the actual work that moves the vehicle. The other 2/3 is converted into heat, of which one third goes out with the exhaust. This leaves the remaining 1/3 in the engine block, requiring the need for a coolant to absorb this heat, transport it to the radiator and dissipate it into to the environment or as heat in the passenger compartment.

Through the removal of this heat by the coolant fluid, the engine is able to operate in an efficient manner. Therefore engine coolant is a generic term used to describe fluids that remove heat from an engine, in effect “cooling” the engine. Not all fluids are efficient heat transfer materials in the extreme setting as found in a combustion engine. Selection of the proper fluid is influenced by the environment in which the engine is used and the interaction of the fluid with the materials that comprise the engine.

Lack of maintenance is usually the
cause for cooling system failure

Should I do this service when it's recommended?

Some environments may expose an engine to periods of extreme cold, requiring the fluid remain liquid in order to function properly. In effect, the heat transfer fluid must be impervious to freezing or expressed in other terms, it must possess “anti-freezing” characteristics. It is for this reason that engine coolant is sometimes referred to as antifreeze. Antifreeze is a more specific term used to describe products that provide protection against freezing. Many people use the terms coolant and antifreeze interchangeably.

However not all engine coolants need to provide freeze protection. This is especially true when equipment is used in tropical climates. In this type of climate you will always need an engine coolant but you may not need the coolant to have freeze protection. Consequently water based coolants are often used in these regions. So in effect, the type of coolant fluid used depends on both the application and the geography/climate in which it is used. 

To keep it simple, let's use the term coolant when describing an engine heat transfer fluid. Conversely, during engine operation the fluid must possess the ability to remain a liquid as it is heated during operation. It must resist the tendency to boil and form vapors as this would reduce its ability to transfer heat. An efficient heat transfer fluid for use in combustion engines may require a low freeze point as well as an elevated boil point ensuring its capacity to perform in all situations encountered in the environment such as those used in your Infiniti's engine. 

Such characteristics are exhibited when glycols are combined with water and for this reason form the basis for all engine coolants. The two main glycols that are used as engine coolants are: ethylene glycol and propylene glycol.

This is an example of a poorly maintained cooling system

In addition to providing freeze and boil protection. Coolants must also contain additives that inhibit corrosion and scale formation in the engine’s cooling system. Modern engine coolants use a mixture of glycol and water or just de-ionized water with corrosion inhibitor chemicals and dyes included to complete the package. Such a combination results in a product that provides the following benefits:

• Effective heat transfer
• Prevention of cooling system corrosion
• Effective boiling point
• Freeze point depression where or if required
• Chemical stability
• Safe for use as directed

Yes. Draining out the coolant and refilling the system removes dirt and rust particles that can clog up the cooling system and cause problems in winter and summer.

Why do I have to do this?

Because it is operating in a hot, hostile environment, coolant will break down over time. Most importantly, the coolant's rust inhibitors get used up, leaving the small cooling passages in your engine and radiator vulnerable to corrosion. Even with these rust inhibitors, some corrosion will inevitably take place, contaminating the coolant with debris.

What happens if I don't do this?

If the rust inhibitors stop working, the cooling system will rust from the inside out. The biggest source of rust in a car's cooling system is the engine block.
In time, these bits of rust will also clog the tiny passages within the radiator and heater, causing your engine to overheat.

Poorly maintained cooling systems will eventually clog the radiator

Is maintenance required between intervals?

Check your coolant level periodically. Your owner's manual will have a recommended interval in which to check the coolant level.

If you check your coolant level when the engine is cold, the coolant should be at or above the "minimum" or "fill" line on the transparent refill container. If you check your coolant level when the engine is hot, the coolant should be at or just below the "max" line.

Disappearance of coolant could be caused by either an external or internal leak, the latter being more expensive. Either one should be addressed quickly, since running low or out of coolant can lead to catastrophic engine failure.

At our dealership, we regularly inspect the cooling system of every vehicle we work on and provide any maintenance recommendations. If there are questions about maintaining your Infiniti, just ask. We're here to help.