I would not recommend to use the LCIII permanently without a fan, especially in case you want to clock it to 33 MHz, add a math. coprocessor and put something into the PDS slot. Consider to buy a low noise fan of appropriate size and rating combined with an electronic fan speed controller. Look for a balanced version. Apple used balanced fans in some LC475s. It might seem to be a little overkill, but you will benefit from this mod any minute you use the machine. The price range for fans of this kind is from 1 to approx. 50 bucks.