In this experimental analysis, the stability of multi walled carbon nanotube based nanofluids with six different base fluids such as water, vegetable oil, engine oil, soap oil, brake oil, and suspension oil are studied. The nanofluids are prepared by the two-step method without the addition of surfactant and at two-volume concentrations. This stability analysis is performed by the UV-Vis spectrophotometer, measuring pH values, and photo capturing techniques. This analysis is carried out at three-time intervals such as at the time of preparation, 15 days after preparation, and 30 days after preparation. From the experimental analysis, the higher order of stability is found to be the multi walled carbon nanotube/water nanofluids, multi walled carbon nanotube/vegetable oil, multi walled carbon nanotube/engine oil, multi walled carbon nanotube/ soap oil, multi walled carbon nanotube/brake oil, and multi walled carbon nanotube/suspension oil-based nanofluids.