One of the most asked questions we get at Evans is regarding our Lifetime Coolant claim. Evans Cooling Systems (ECS) has always contended that if a cooling system using Evans Waterless Coolant is not contaminated with water, it will last the lifetime of the vehicle. Our argument for this is based on three elements, and they are as follows:
- Historical Anecdotal Customer Feedback
For over twenty years, ECS has been selling, marketing, and distributing waterless coolant. During that time, we have sold millions of gallons of Evans coolant, and have converted over ¾ million vehicles to Evans coolant worldwide. From time to time, we get emails, phone calls and letters from some of our early customers, telling us how happy they are with our coolant, and how long they have had it in their vehicles. Some of these customers have had our coolant in their vehicles for ten years or better, without issue. In China, ECS’ affiliate has been converting brand new cars to Evans coolant for the past ten years through new car Evans dealership conversion centers (over 600 and growing). Most of these cars are still on the road and reporting no coolant-related issues to speak off. Certainly, this is not a scientific affirmation of our lifetime coolant claim, but for us at ECS, it validates what our customers already know, that the coolant continues to function as it was designed to do, well after most water-based coolants may have failed or been replaced.
2. No Top-offs
What does no top-offs have to do with the Evans Lifetime Coolant claim? It is generally well-known in water-based coolant manufacturing circles that most water-based cooling systems need to be topped off periodically, depending on the duty cycle of the vehicle. Mike Goodheart of Penray says, “Even the new trucks today will lose coolant. Over the course of a year, an average fleet will use about half its capacity of antifreeze. So if you've got 100 trucks that each have a 12-gallon coolant capacity, you'll use about 600 gallons per year. So there are constantly challenges to keep the coolant in good condition."
How does stealth coolant loss happen?
There are several sources of water vapor (steam) in the cooling system of a heavy duty engine that uses water-based engine coolant. Localized boiling in the cylinder head may occur while the engine is under a sustained heavily loaded condition, and is exacerbated by high ambient temperature and high altitude operating conditions. Also, stored heat within the cylinder head of an engine that has been worked hard and then abruptly shut-down will attempt to dissipate into coolant that is no longer circulating, causing the coolant to boil (aka after-boil).
It is important to note that 1) when 50/50 ethylene glycol/water coolant is boiled, the glycol portion condenses immediately, leaving the water vapor behind, and 2) water vapor only condenses at a temperature that is lower than the boiling point of water for the pressure of the system. Of significance is that while the water vapor is present, it occupies a volume that displaces liquid coolant. When the volume of vapor becomes great enough, the cooling system pressure increases enough to open the pressure relief valve in the cap on the expansion tank. The release is likely a mist of liquid coolant, depleting the coolant in the system. Although a puddle on the ground may not be seen, the coolant has been lost and, after repeated such losses, must be replaced periodically through top-offs.
How does Evans Coolant stop stealth coolant loss?
There are many differences between water-based coolants and Evans coolant, but the one that counts in vapor avoidance is this: Evans coolant separates the operating temperature of the coolant from its boiling point. With a conventional or slightly warmer operating temperature and a boiling point of 190⁰C, that separation is readily understood. In the cylinder head, any locally-generated vapor condenses immediately into surrounding coolant that is much colder than its boiling point. On an abrupt shut-down, Evans coolant has the capacity to absorb all of the stored heat in the cylinder head without reaching its boiling point, which means no coolant loss, i.e., no top-offs. By preventing coolant loss from happening in the first place, you have removed one of the barriers in producing a lifetime coolant.
- The Need to Periodically Change Water-Based Coolant
Most engines use water-based coolants containing similar base fluids: a 50/50 mix of ethylene glycol and water. In some instances, industrial engines may utilize other base fluids, such as a mixture of propylene glycol and water, or simply water alone. In addition to the base fluid, there are a small amount of other ingredients including corrosion inhibitors, antifoams, dyes and bitterant. While these other ingredients are only a small fraction of the total formulation, they are what differentiate one coolant from another.
Historically in North America, conventional coolants have typically used a phosphate/ silicate mix as the main components in their inhibitor system. Inhibitors such as these are characterized chemically as being inorganic, and work by forming a protective blanket that actually insulates the metals from the coolant. Because these inhibitor systems are depleted by forming a protective layer, conventional coolants need to be changed at regular intervals, typically every two years.
Due to the demands on modern engines, new technologies have been developed to protect engines from corrosion. Some changes have been driven by water quality issues. In some locations in the world, problems with hard water minerals forced coolant technologies to be phosphate-free. Calcium and magnesium, minerals found in hard water, react with phosphate inhibitors to form scale on hot engine surfaces. Not only does the scale form a thermally insulating layer on the metal surfaces, it contributes to inhibitor depletion. Modern coolants contain organic acid corrosion inhibitors such as sebacic, octanoic, 2-ethylhexanoic acid, and others. Depending on the type, they can also act as scale inhibitors. Like inorganic inhibitors, organic acids can also be depleted over time as they provide corrosion protection. They are also susceptible to depletion as corrosion products, such as iron ions, bond with them to form precipitates.
In general, water-based coolants degrade over time as the ethylene glycol breaks down into primarily glycolic and formic acids. Degradation occurs more quickly in engines operating at higher temperatures, or those that allow more air into the cooling system, and is usually duty cycle-dependent. The end effect is that no matter which water-based technology you use, the fluid’s integrity will be compromised over time, and corrective action will need to be taken, which means in many instances, a coolant change-out.
How does Evans help stop coolant change-outs?Evans has always contended that the absence of water in a cooling system removes the root causes of metal corrosion, electrolysis, and high system pressures. The inhibitors are not consumed in the same way they are in a water-based coolant. Thus Evans has the potential to last for many years without needing to be replenished or replaced.
To this point, over the years, ECS has collected many used coolant samples from cooling systems that were subjected to severe and prolonged conditions. The chemical analyses of these samples showed that in most instances, the fluid had retained its integrity, and inhibitor levels were still robust. It was only in instances in which excess water was present (levels beyond that allowed at installation), that any significant inhibitor depletion had occurred. In those cases, there was evidence that corrosion was beginning.
Moving forward, ECS is always striving to improve the quality of its products through quantitative engineering & testing programs designed to optimize the performance of its fluids. At its core, Evans is a technology-driven company whose goal is to market products that will work as advertised, and provide a real benefit to the end user.