Nanodiamond (ND) particles dispersed in ethylene glycol/water mixtures have been reported for their thermal properties and potential heat transfer applications. Commercially available ultra-dispersed diamond soot was treated with sulfuric acid-nitric acids to form single ND particles - characterized by various techniques - then prepared ND nanofluids and then measured thermal conductivity and viscosity by experimentally. The enhanced thermal conductivity for 1.0% of ND/20:80, ND/40:60 and ND/60:40 nanofluids is 17.8%, 14.2% and 11.4%; enhanced viscosity is 2.74-times, 1.73-times and 1.92-times at temperature of 60 degrees C, respectively. The heat transfer benefits of ND nanofluids in laminar to turbulent flow have been analyzed theoretically by using thermal properties. (C) 2015 Elsevier B.V. All rights reserved.