There is a critical need for improved coolants for military aircraft applications. The objective of this research is to evaluate nanofluids as potential replacement for the coolant currently used by the Air Force. Alumina/DI water nanofluids were evaluated. It was observed that at the same volumetric flow there was no significant improvement in convective heat transfer. Problems associated with the nanofluids were observed: increase of pressure drop with concentration, particle settling, and especially evidence of vaporization promoted by the nanoparticles. Results raised doubts about the applicability of using nanofluids as alternative coolants for avionic applications.