By: Jason Giacchino
Email: offthepegs@atvsource.com

January 2007

Let's Talk Antifreeze

Today’s topic comes to us from a variety of alert readers who have questions about antifreeze, and the logic behind choosing from an ever- increasing list of available engine coolants. No doubt due to the fact that winter’s grip has spread across much of the country, let’s take a look at the weird and wonderful world of antifreeze.

We’ll start by reminding you of a truth that you’ve certainly heard before--water disperses engine heat more efficiently than any chemical can. Sure it would be convenient to fill our ATV radiators with good old H2O straight from the garden hose but there are four fundamental flaws in running straight water.

1. Water freezes at 32 degrees F.
2. Water boils at 212 degrees F.
3. Water contains sediments that can build up in your cooling system.
4. Water induces corrosion of bare metal.

The freezing is self-explanatory as many riders around the globe (myself included) are forced to store our machines in temperatures that dip well below the freezing point of water for months at a time. Since modern four-stroke mills typically operate between 230 and 250 degrees, a 212 degree boiling point would spell disaster. Finally, while tap water looks clear and pure, the truth of the matter is that it is loaded with minerals such as calcium and lime that leave behind a scaley residue as they flow. After a few cycles, residue will inhibit the water’s ability to make contact with the heated engine surface thus defeating the entire purpose of the cooling system.

For these reasons mixing distilled water with antifreeze is strongly recommended. Distilled water removes much of the sediment by the distillation process (which essentially pre-boils the water to separate the heavy minerals). While distilled water solves the issue of the sediment, there are still freezing and boiling temperatures to contend with as well as the fact that metal when mixed with water equals instant corrosion. Enter the antifreeze solution.

Antifreeze, or more accurately engine coolant, is a chemical mix that relies upon Glycol to raise the boiling point and lower the freezing point of the water. Glycol typically comes in two forms--Ethylene and Propylene. Ethylene works better and costs less than Propylene but is extremely toxic. In addition to glycol, most coolants contain corrosion inhibitors such as silicates which slow the process of water’s harsh effects on bare metal.

You're probably wondering if coolant is so effective, why mix it with water at all. The answer is within the opening sentence of this report: Water disperses heat more effectively than any chemical alone. Modern engines still benefit from water’s ability to transfer heat away from the block but simply require antifreeze to compliment the water’s natural ability.

Now down to the nitty gritty: The ATV (as well as the motorcycle industry) recommends that you do not use automotive antifreeze in your radiator. While this was initially viewed as hype and an attempt for dealers to rake in extra income in chemical sales, the truth of the matter is that there are some benefits to running motorsport specific coolant. The main benefit is seal life. Because an automotive cooling system covers much more surface area than an ATV’s, auto antifreeze typically contains a much higher concentration of corrosion inhibitors which are abrasive enough to damage smaller ATV seals. This is why many motorsport specific coolants contain a water soluble silicone additive to provide lubrication to the water pump seal.

Anti-foaming properties offer another benefit of running motorsport developed coolant in your quad’s cooling system. Complaints that it may cost a bit more than the readily available automotive antifreeze are nullified by the potential expense of a seal failure which could contaminate your ATV’s engine oil with water. Not to mention most motorsports engine coolants come ready to use (already mixed 50/50) saving you the expense of having to purchase a gallon of distilled water.

Taking care of your engine’s cooling system is an essential, yet oft overlooked area of maintenance. Remember to change the fluid as often as after every ride if you race or ride your machine in extreme heat (such as the desert). Casual trail riders can defer to a change once per season. Follow these tips and the benefits will become clear on both the hottest days and coldest nights of the year.