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Questions & Answers

Published: 16/03/2015

The Big Question?

Q. What’s the problem with water and why should I convert to Evans?

This is the key question which requires a multifaceted answer – but well worth reading if you have 10 minutes to spare!

Water - great for drinking but not ideal for engine cooling

First used in engines some 100 years ago, water-based coolants are universally acknowledged to have inherent physical and chemical limitations that effect long-term reliability, increase maintenance costs and often restrict engine performance.

Statistics published by manufacturers and motoring organisations confirm, that water is the root cause for 60% of engine breakdowns and 40% of catastrophic failures. Whilst internal damage goes mostly unnoticed in new engines, the cumulative effects of corrosion, cavitation and cyclic pressurisation become increasingly apparent over time.

For decades engine designers and antifreeze formulators have persisted with water whilst endeavouring to overcome its intrinsic shortcomings - primarily because there has been no viable alternative. Jack Evans, a cooling system designer, also struggled for many years with waters limitations and was determined to find a better solution. Finally, in 1993, Jack formulated a synthetic coolant which eliminated corrosion, erosion, overheating, significantly reduced system pressure and maintained heat transfer equilibrium.

Over the last twenty years Evans waterless engine coolants have been tested and proven by OEM’s, fleet operators, racing teams, professional restorers, plant operators and automotive aficionados to increase reliability and reduce operating costs.  The high boiling point of Evans coolants are also facilitating improvements in engine design, performance and fuel economy.

Evans products are certified non-toxic and documented to last 20 years without need for replacement or top-up. So, if you are considering an environmentally friendly coolant that improves and extends the life of your engine please read on....

• Water-based coolants need to be drained and replenished every 1 to 4 years, because the corrosion inhibitors breakdown* over time (*depletion by oxygen and galvanic activity).

• Evans has been proven to last more than 20 years and could reasonably be considered as ‘The coolant for engine life’. Just imagine, the possibility of an engine with no coolant filler cap and no need to top-up or change the coolant, ever!

• The effectiveness of water-based coolants are subject to their quality, metal compatibility and regular renewal. If the coolant quality is poor (cheap), incompatible or not renewed regularly then corrosion (via oxidation and galvanic activity) will quickly take hold and damage/failure is inevitable. According to the BTC Testing Advisory Group (BP, Shell, Arteco et al) “60% of engine failures are caused by cooling system failure”. So it is reasonable and factual to state ‘the problems associated to water-based coolants are confirmed and extensive’.

• Evans does not oxidise inside an engine or support galvanic activity, effectively eliminating all corrosion – permanently!

• Water freezes at 0ºC and so water-based coolants must contain sufficient antifreeze (usually 50% Toxic Ethylene Glycol) to prevent freezing in winter. If the antifreeze concentration has been depleted or diluted over time then major freeze damage can occur.

• Evans has natural antifreeze properties freezing below -40ºC, does not degrade inside a cooling system and is Non-Toxic. Thus eliminating the worry about topping-up or recharging with antifreeze every winter.  

• Under normal atmospheric conditions water turns in to steam at 100ºC. Mixing ethylene glycol antifreeze with water (50-50) increases the boiling point to 103ºC. Fitting a spring loaded cap can raise system pressure and thus the coolant boiling point. A typical 1 Bar (14.5psi) rated pressure-cap theoretically raises the boiling point of 50-50 coolant to 123ºC, which should be sufficient to prevent boiling. In reality Eddy currents and pressure drops within the cooling system, combined with very high metal temperatures adjacent to the combustion zone often result in boiling coolant and the formation of steam-vapour pockets. Steam is a poor heat transfer medium and localised overheating is often the cause of pre-ignition, detonation, increased fuel consumption and reduced power delivery. Once a steam-vapour pocket is formed it will not readily condense and can lead to full-overheat, piston-liner scuffing, cylinder-head warping and eventually total engine failure. Sounds dramatic, especially when you’re stood next to an engine that ‘lets-go’!

• Evans has a boiling point above 180ºC which ensures it will not boil or turn to vapour inside an engine. By remaining as a liquid under all engine loads effective heat transfer is maintained. Engines filled with Evans usually run 3 - 10ºC hotter than those using water-based coolants, but the overall heat transfer and engine efficiency is improved through the elimination of steam-vapour pockets. The lube-oil temperature also runs 3 – 10ºC hotter with Evans but >500,000 successful conversions confirm this has no detrimental effect.

• Water-based coolants turn to steam-vapour where there is sufficient temperature combined with a drop in pressure. The rapid formation of vapour bubbles inside a liquid is better known as Cavitation. If the local pressure increases rapidly the vapour bubble will collapse with significant force, enough in fact to erode metal. The process of rapid cavitation and bubble collapse adjacent to engine liners is a common cause of erosion – sometimes to the point of catastrophic liner failure. Because car engines liners are usually cast within the main block it is impossible to see if cavitation-erosion is occurring. However large diesel engines are fitted with removable (wet) liners, which are often replaced due to severe erosion - in the form of deep pitting. In an attempt to reduce wet-liner pitting additional nitrite and nitrate inhibitors are often added to heavy-duty coolants. A similar form of cavitation-erosion can occur inside pump chambers (volutes) and the associated impellers. Pump and impeller erosion results in reduced coolant flow rates and an increase in overheating.

• Evans coolants have a much lower vapour pressure compared with water-based coolants, which means they are far less prone to cavitation or causing cavitation-erosion. In a John Deere cavitation test, now adopted by the SAE, Evans reduced liner pitting by 90% in comparison to John Deere’s own heavy duty water based coolant.

• Water generates high vapour pressures as its temperature increases – approx 1 Bar (14.5psi) at 100˚C. These pressures exert internal stress on all cooling system components, especially hoses, pump seals and radiator seams. When the engine cools the pressure reduces. i.e. the process is cyclical and repetitive, which often leads to fatigue and component failure. E.g. burst hoses and burst radiator seams.

• The low vapour pressure generated by Evans coolants makes it possible to (carefully) remove the radiator or expansion bottle cap whilst the engine is running and eliminates internal stresses on hoses, pump seals and radiator seams, thus extending operating life by many years and preventing breakdowns.

General Questions

Q. What is bad about water in a coolant?

A.The boiling point of water is only 100°C.
B. Because an engine operates very close to the boiling point of water,(within the engine block and cylinder head boiling actually occurs), thus causing pressure within the cooling system.
C. The boiling point of water is the failure temperature of the cooling system.
D. Water vapour (steam) has almost no thermal conductivity.
E. Water is aggressive toward cooling system metals and promotes electrolysis between dissimilar metals within the cooling system.
F. Water contains Oxygen which encourages corrosion in any cooling system. Q. Which Evans Waterless Coolant is correct for my vehicle or equipment?

A. Vintage Cool 180° is specially formulated for increased yellow metal content and porous cast irons found in Vintage engines.
B. Classic Cool 180° is specially formulated for engines with more cast steel and iron, with reduced levels of copper and the introduction of aluminum products.
C. Power Cool 180° is specially formulated for high performance engines, with significant aluminium components.
D. Powersports 180° is specially formulated for track & trail bikes.
E. Heavy Duty Coolant is specially formulated for engines driving trucks, buses, plant etc. and contains increased inhibitors to ensure an operating lifespan of 15 years or more.
F. Aero Cool 180° is specially formulated for Rotax engines.

Q. What is the primary purpose of an engine cooling system?

A.To keep engine metal temperatures under control.

Q. What is pump cavitation and how can it occur?

A. Action of the coolant pump creates a low pressure area at the pump inlet. Pump cavitation occurs when coolant near its boiling point encounters the low pressure area and flash vaporises (creates steam) within the pump. The gas pocket in the pump causes the pump to stop functioning and coolant circulation to stop. Coolant pump cavitation leads directly to catastrophic cooling system failure with the coolant being expelled from the system as steam pressure exceeds the pressure relief setting of the cap.

Q. How does Evans Waterless Coolant prevent pump cavitation?

A. The low pressure area of the coolant pump is never at a low enough pressure to flash vapourise. The pump never gets vapour bound and has the capability to pump coolant over a broad range of temperatures.

Q. What is after-boil?

A. After-boil occurs after shut-down of a stressed engine when the coolant is near its boiling point and residual heat remains in the cylinder head. Upon shut-down the coolant pump ceases to circulate coolant through the cooling system. Residual heat boils the stagnant coolant, making steam pressure that exceeds the pressure relief setting of the cap. Coolant is pushed out of the system.

Q. How does Evans Waterless Coolant prevent after-boil?

A. After shut-down, the huge separation between the operating temperature and the boiling point of Evans Waterless Coolant has the capacity to absorb heat from hot metal parts of the cylinder head, boiling is avoided and there is no build-up of pressure to force coolant out of the system. Stresses on cylinder heads are also avoided as metal temperatures are kept under control.

Q. How does Evans Waterless Coolant prevent engine hot spots?

A. The huge separation between the operating temperature and the boiling point of Evans Waterless Coolant provides an environment where any locally generated coolant vapour immediately condenses into adjacent liquid coolant. vapour cannot then build into an insulating barrier, and contact between hot metal and liquid coolant is maintained at all times. Metal temperatures remain under control at all times.

Q. How does Evans Waterless Coolant prevent cylinder liner cavitation erosion?

A. Cylinder liner cavitation erosion is a problem in water-based coolant systems. As the piston moves inside the cylinder there is vibration of the liner. The vibration of the liner against the coolant alternately makes low and high pressures. During the low pressure instant, vapour is created by flash vaporisation. During the adjacent high pressure instant, the vapour collapses against the cylinder liner. This repeated action causes an attack against the metal liner, resulting in cavitation erosion. Evans Waterless Coolant contains no water to allow flash vaporisation and therefore removes the threat of cylinder erosion.


Q. What is Evans Waterless Coolant made of?

A. Evans Waterless Coolants are patented synthetic non-toxic liquids blended with a non-aqueous proprietary inhibitor package.

Q. Do I have to add antifreeze to the Evans Waterless Coolant?

A. No, Evans Waterless Coolant has an antifreeze protection built in to protect to -40°C.

Q. Is Evans Waterless Coolant toxic?

A. No, Evans Waterless Coolants contain Evans patented DeTox™ additive and has been classified as Non-Toxic by an EPA certified laboratory. However as with all chemicals, do not consume. Keep away from children. Avoid contact with eyes and skin. Rinse hands and eyes with water after incedental contact.

Q. Does the colour of Evans Waterless Coolant products indicate any difference within the formulation of the Coolant?

A.Yes, All Evans Waterless Coolant is based on a proprietary inhibitor blend, the colour denotes the formulation specific to vehicle type.
A. Green denotes a Classic Formulation
B. Purple denotes a Vintage Formulation

Q. What are various boiling points of interest?

A.Water at sea level (1 atm. absolute) boils at 100°C.
B. Water at sea level with a 1 atm. pressure cap (2 atm total) boils at 121°C.
C. EGW at sea level (1 atm. absolute) boils at 106°C.
D. EGW at sea level with a 1 atm. pressure cap (2 atm. total) boils at 128°C.
E. Evans Waterless Coolant Waterless Coolant at sea level (1 atm. absolute) boils at 180°C.

Q. How do the additives in Evans Waterless Coolant remain in solution without the presence of water?

A.Evans Waterless Coolant contains no additive that requires water to dissolve or to enable the additive to function

Q. How long will Evans Waterless Coolant last?

A.4LIFE, Evans Waterless Coolant will last the life of the engine as long as it is not contaminated with water.

Q. What happens to the boiling points at higher elevations?

A.Boiling points decline as altitude increases. A. Water at 5000 ft. (0.83 atm. absolute) boils at 97°C.
B. EGW at 5000 ft. (0.83 atm. absolute) boils at 103°C.
C. Evans Waterless Coolant at 5000 ft. (0.83 atm. absolute) boils at 176°C.

Q. What is the Reserve Capacity made available by changing to Evans Waterless Coolant?

A. The huge separation between the operating temperature and the boiling point of Evans Waterless Coolant unlocks a Reserve Capacity that already exists in systems designed for water-based coolants. Any cooling system designed to keep coolant below the boiling point of water depending on the pressure of the system under all operating conditions and after shut-down is liberated from those requirements with Evans Waterless Coolant. When temperatures happen to be higher, there are no failures due to the lower boiling point of water. In a 38°C environment (under bonnet) a radiator that is 121°C will dissipate 25% more heat than one at 104°C.


Q. Do I use the same volume of Evans Waterless Coolant in my cooling system as before?

A.Yes, Evans Waterless Coolant thermally expands to within 1% of 50/50 water based coolants at 100°C so you can use the existing fill level in your cooling system for Evans Waterless Coolant.

Q. How much water is acceptable after a conversion to Evans Waterless Coolant?

A.In all conversions, ideally water content must not exceed 3.0%.

Q. How do you test for the percentage water content?

A.The water content is readily determined by the use of a refractometer .The following are refractometer readings of Evans Waterless Coolant with corresponding water content percent:
R.I. Reading:  Evans Waterless Coolant
1.43181         0% Water by volume
1.43085         1% Water by volume
1.42986         2% Water by volume
1.42935         3% Water by volume
1.42882         4% Water by volume
1.42749         5% Water by volume

Q. What will happen if I do not achieve the recommended 3% water content?

A.Even at above 3% water content Evans Waterless Coolants will still out perform all traditional water based coolants. However for high performance and arduous conditions full benefit may not be realised. If the conversion guidelines are followed, rarely does the water content exceed 3%.

Q. Can I add water to Evans Waterless Coolant?

A.Yes, but only in an emergency. Evans Waterless Coolant is completely miscible with Water, however once you exceed 5% the benefits of Evans Waterless Coolant are compromised. We recommend that as soon as possible you refill with Evans Waterless Coolant to regain its benefits.

Q. What should I do with the old coolant out of my vehicle?

A. Traditional antifreeze/coolants are toxic and should be disposed of in accordance with the local regulations.


Q. What is the most important operational feature of Evans Waterless Coolant?

A.The huge separation between the operating temperature and the boiling point of the coolant, in the order of at least 80°C

Q. Will Evans Waterless Coolant cause my engine to run at a higher temperature?

A.The operating temperature of the engine and coolant may increase slightly, by approximately 3-7 degrees. However the temperature inside the engine will be consistent and steam vapour will not be produced. i.e engines often run cooler with Evans Waterless Coolants.

Other Coolants...

Q. Which engine coolants are water-based?

A.All commercially available engine coolants, (usually in a 50/50 water / coolant formulation).Evans Waterless Coolant is the only non water-based coolant.

Q. What unique limitations are there on a functioning cooling system using any water-based coolant?

A. The cooling system must keep the coolant below the boiling point of water depending on the pressure of the system, under all operating conditions and after shut-down. This task is difficult because the coolant frequently operates close to or at the boiling point of water.

Q. Water-based coolant is mostly 50% glycol and 50% water. Why isn’t the critical temperature the boiling point of the mixture, rather than the boiling point of water?

A.The critical temperature of a mixed solution will always be the boiling point of the weakest solution, water turns to steam vapour and is the weakest solution in the mixture, Some locations within the cylinder head generate so much heat that some of the nearby coolant boils. When local coolant boils, the resulting vapour is nearly 100% water vapour. If the coolant that is surrounding the water vapour is above the boiling point of water, the water vapour cannot condense. Under this condition, the water vapour makes an insulating barrier between hot metal and liquid coolant, causing the temperature of the metal to spike to high levels.

Q. Why is the vapour from boiling a 50/50 glycol/water mixture (EGW) nearly 100% water vapour?

A.When the mixture is boiled the water part is fractionally distilled, as it is far more volatile than the glycol portion. Water vapour is liberated while the glycol remains in the solution.

Q. What is the difference between Blue/Green and Red/Pink/Orange coolants?

A.Colour, there are however some general industry guidelines; A. Most blue/green coolants have non OAT (organic acid technology) inhibitors, contain silicates and phosphates in their inhibitor package and should be changed every two years.
B. Most red/pink and orange coolants contain OAT inhibitors and can last three to five years.
C. From the 1990,s most manufacturers have started using HOAT (hybrid organic acid technology). HOAT based coolants can last three to five years. These have no particular colour scheme. (The above three products must not be mixed together).


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