Because it is flammable and it has poor staying power when compared to light machine oil. It also does not lubricate nearly as well as machine oil. Its primary advantage is that it is a SOLVENT and will cut through corrosion and temporarily lubricate at the same time. I won't use it in or near electronics, ever. (besides that, it stinks)
We're only talking about a drop, but I have to agree, light machine oil is a better option. My point was, the bushing lubricant drys out and causes most of these fan issues. The oil is a quick and easy fix.
Edited by mailiang, 17 November 2014 - 05:55 PM.