Waterless Engine Coolants

New Subcommittee D15.22 Paves the Way for Innovation

Water-based coolant (right) has begun to boil away, while waterless coolant has not begun to boil.

An effective engine cooling system is essential to keeping any vehicle running properly. In recent years, waterless engine coolants have emerged as one option for cooling systems. In order to recognize this innovation and encourage standardization, ASTM International Committee D15 on Engine Coolants and Related Fluids created Subcommittee D15.22 on Non-Aqueous Coolants in 2010.

According to Mark Stone, director of business development, Evans Cooling Systems Inc., Suffield, Conn., non-aqueous coolants have boiling points that are much higher than aqueous-based coolants. The primary virtues of non-aqueous formulations stem from the absence of water vapor that is frequently present in cooling systems that contain water. Water, in its liquid state, has superior heat transfer capabilities but, in its gaseous state, transfers heat poorly.

While non-aqueous coolants currently apply mostly to liquid cooled internal combustion engines, they also have applications in solar and other areas in which the low boiling point of water is a barrier.

Non-aqueous coolants conform to many ASTM International standards for engine coolants, but there is a need for standards that are specifically focused on non-aqueous products. D15.22 is at work on three proposed standards.

  • WK34987, Test Method for Thermal Conductivity of Non-Aqueous Engine Coolants — The development of a practical, standardized test for thermal conductivity of non-aqueous engine coolants is needed for comparison against specifications to be set for these fluids.
  • WK38624, Test Method for Corrosion of Cast Aluminum Alloys in Non-Aqueous Engine Coolants Under Heat-Rejecting Conditions — This proposed standard is needed to provide a tool for evaluating non-aqueous coolants with regard to aluminum corrosion.
  • WK38801, Test Method for Foaming Tendencies of Non-Aqueous Engine Coolants in Glassware — Needed as a screening tool for candidates for non-aqueous engine coolants, WK38801 covers a simple glassware test for evaluating the tendency of non-aqueous engine coolants to form under laboratory-controlled conditions of aeration and temperature.

“The standards developed by D15.22 will be useful in protecting the consumer from unscrupulous companies looking to pass off a product as a waterless coolant that could not meet these standards and could potentially cause the consumer confusion, money or injury,” says Stone, who is the secretary of D15.22. “The proposed standards will provide added credibility to the technology, especially with original equipment manufacturers for trucks, cars and buses, as well as fleet managers who often require that any new products meet standards.”

More information can be found at D15.22’s page on the ASTM website. All interested parties are welcome to join in D15.22 standards developing activities.

Stone notes that planning for the future is a central motivating factor for D15.22.

“The twin efforts to improve emissions strategies and to gain greater fuel efficiencies will push coolant temperatures ever higher,” says Stone. “We expect that the demand for products that can work within that framework will include a movement toward non-aqueous coolants. I expect that, given the objectives at hand and the limitations of water-based fluids, the work we are doing will be extremely important.”

This article appears in the issue of Standardization News.