The rapid developments of nanotechnology have led to emerging of a relatively new class of fluids called nanofluids, which could offer the enhanced the thermal conductivity. The diathermic oil (DO) is a kind of traditional heat transfer fluids commonly used in many fields such as energy storage systems, cooling systems and heating control system. Therefore, the enhancement of diathermic oil thermophysical properties by using nanoparticles would be beneficial for the performance of the energy systems. With the purpose of filling the research gap in the literatures, this paper presents experimental data of thermal conductivity and viscosity properties of DO-based SiC nanofluids. It was found that the thermal conductivity of nanofluids increased with the volume fraction, and the highest thermal conductivity enhancement was found to be 7.36% for 0.8 vol.% nanofluid at 50 degrees C. The prepared DO/SiC nanofluids behaved Newtonian behavior and the viscosities decreased with the increasing temperature. In addition, the overall effectiveness of nanofluids decreased with the increase of temperature, which indicated potential applications for energy systems in high temperature. (C) 2016 Elsevier Ltd. All rights reserved.