Assessment of the Validity of Conductivity as an Estimate of Total Dissolved Solids in Heavy-Duty Coolants

摘要

Conductivity is widely used in the analysis of heavy-duty coolants to estimate total dissolved solids. TDS is of concern in heavy-duty coolants because the practice of adding supplemental coolant additives (SCAs) to the coolant can lead to overloading and to subsequent water pump seal weepage and failure. Conductivity has the advantage of being quick and easy to measure and the equipment is inexpensive. However, questions are continually raised as to whether conductivity truly is a valid method of estimating TDS and, if so, over what concentration range. The introduction of new chemistries in heavy-duty coolants and new extended service interval (ESI) technologies prompts a critical assessment. Conductivity and TDS measurements for all of the coolants and SCAs used in heavy-duty engines in North America will be presented. The effects of glycol concentration on conductivity will also be examined.