Potential Issues with Waterless Engine Coolants
Andy Published on Friday, August 1st, 2014
Below is an interesting US-based article I received a short while ago. This is not intended to bash any particular manufacturer of waterless coolants; it is just a challenge to the technology used.
“Many concerns have been raised to us in recent months regarding the effectiveness of Waterless coolants and the inherent dangers they may possess. We have spent some time researching the product and would like to make all our customers aware of our findings.
Waterless products are 100% glycol, some are 100% propylene glycol, and others are a mix of propylene glycol and ethylene glycol. They are slippery when spilled or leaked onto the tarmac. Assuming a baseline friction co-efficient reference of 1.00 for dry pavement, the friction coefficient of water is 0.65. The friction coefficient of Waterless products is 0.16, four times less than water. Some race circuits in America are now prohibiting the use of engine coolant that contains ANY glycol due to this fact.
The other and more pressing reason that Waterless products are prohibited at race circuits is that they are flammable. With flash points in the range of 110-130°C if the Waterless coolant were released at or above the flash point, it could ignite. Coolant temperatures can be observed in this range during actual operating conditions, making this a real risk. Reports have also been made of damage caused by glycol coolant fuelled fires, in some instances, destroying whole cars and resulting in thousands of pounds worth of damage.
The NHRA rule change regarding glycol coolants was the result of a terrible fire where the competitor was using Waterless coolant in his car. The engine pushed a head gasket and the coolant caught fire which came under the seat resulting in a cockpit fire. Glycol coolants are now prohibited in the NHRA. In another case the Motorsport South Africa ASN prohibited the use of glycol on safety grounds “In the case of both cars and motorcycles, the use of glycol-based coolant additives is prohibited.”
In addition, the operational downside is the decreased ability to transfer heat compared to water based coolants. Waterless coolant should never be advised in applications where heat issues are apparent, Waterless coolants will only compound this problem as they lack the necessary heat transfer properties to provide a solution.
Although the product is a very good corrosion inhibitor, it will not adequately protect an engine when overheating. The Waterless coolants cannot transfer heat as efficiently as water, thus causing an engine to run hotter. The engine will continue to run hot until a critical component fails as the boiling point is so high.
To summarize:
Engines can run 45-60°C hotter (at the cylinder heads) with Waterless products.
Stabilized coolant temps are increased by 15-25°C.
Specific heat capacity of Waterless products ranges from 0.64 to 0.68, or about half that of water.
Engine octane requirement is increased by 5-7 numbers reducing engine horsepower by 4-5%.
Viscosity is 3-4 times higher than what OEM water pumps are rated to accommodate.
Coolant flow rate through radiator tubes is reduced by 20-25% due to the higher viscosity.
Race circuits are starting to prohibit waterless products because they are flammable and cause a slippery surface hazard when leaked.
When speaking to a classic car specialist recently the subject of Waterless coolants was brought up.A Waterless coolant manufacturer had given them product sponsorship ahead of classic Le Mans 2012, in FP1 the car stopped on track with smoke billowing out of bonnet. On closer inspection the coolant had plasticized and warped the head, the coolant then passed through the head gasket hydraulic locking cylinder one. The damaged cause was very costly and ended the team’s weekend early, it is not a product they would recommend or use again.”
We sold a waterless coolant for a short while but stopped over a year ago. We never encountered any issues although it sounds like potential issues are more “race” related. However, I thought we would be remiss if we did not share this information with you as it opens a valuable debate into the safety and efficacy of such technologies versus conventional water based cooling products.
As FuelTechExperts is promoted as an unbiased source of information it is only fair that Evans have the opportunity to respond.
Response from Evans below:
“Thank you for the opportunity to relay our side of the debate here.
Glycol is slippery. As I said to the technical director in the American Flat Track Series, any fluid is slippery on the track. What’s important is keeping the fluid off the track in the first place. Our coolant does not build vapor pressure, so it doesn’t boil out when it gets hot like antifreeze or water. Our coolant is legal in flat track and some road race motorcycles series. I road raced motorcycles with waterless coolant for 15 years without incident. I wouldn’t ask anyone to do something that I haven’t done myself.
All glycol based coolants are combustible, this includes water-based antifreeze. The “flash point” is the same for waterless and water-based coolants, go ahead and google “gylycol fire”. Flash point does not mean that it will spontaneously ignite, there must be a flame source present. The auto-ignition temperature is significantly higher, somewhere up above 700F. Again, this behavior is common with water-based antifreeze as well.
The heat transfer of waterless coolant is a little less than with water-based antifreeze just as water is a better conductor of heat than antifreeze. A cooling system is “air side limited”, however, which means that the heat transfer between metal and liquid is insignificant compared to the heat transfer between metal and air at the radiator. The radiator efficiency is based on the temperature difference between the radiator metal and the air temperature. The greater that temperature difference, the better the transfer efficiency. Runaway temperatures are a problem with water-based antifreeze, not waterless coolant because when the water boils to vapor inside the engine virtually all cooling capacity is lost. The metal temperatures will spike by hundreds of degrees creating the detonation-causing hot spots and head warping that is associated with overheating. If our coolant temperatures rise above normal, it doesn’t vaporize and the liquid to metal contact is not lost. With a higher coolant temperature, the radiator efficiency improves because of the larger difference between metal and air temperatures; the system will reach equilibrium rather than spiking.
Octane is needed to delay detonation of the fuel mixture. A lower octane can actually be used with our coolant because hot spots are not formed.
The viscosity of our coolant at operating temperature is very close to that of antifreeze, again, not an issue.
Like radial tires and disc brakes, not everybody will accept a new technology at the start; we are offering an advancement in engine cooling and everyone needs to make their own decisions.
John Light -Evans Powersports Coolant Director”
