Stable surfactant-free Al2O3/deionized (DI) water nanofluids are prepared by a two-step process and are stabilized using an ultrasonic homogenizer. The thermal conductivity enhancement measured by a transient hot wire technique demonstrated a nonlinear relationship with increase in volume fraction of dispersed nanoparticles and attains a maximum enhancement of 15% for 1vol% of Al2O3 loading in deionized water at 70 degrees C. The stabilized Al2O3/DI water nanofluids were employed as the working fluid in a screen mesh wick heat pipe placed horizontally. The straight heat pipe configuration is altered for more practicality in use, with crimped edges, extended conduction lengths, and minute surface depressions. The heat pipe is tested at various levels of heat inputs and concentrations of Al2O3 nanoparticles. The evaporator section is heated by circulating water through a heating chamber, and the condenser section is cooled under free convection. The experimental results show an optimum reduction of 22% in the thermal resistance value using 1vol% of Al2O3/DI nanofluids as compared to DI water at low heat input of 12W. The stabilized operation of the heat pipe is observed at high heat input of 73W and at low concentration of 0.005vol% Al2O3/DI water nanofluids. The findings emphasize potential for nanofluids as future heat pipe fluids.