When geared like my above post I doubt you'll ever need a fan. My nephews LST is on 4s geared very similar and the Castle 2200kv is fine temp wise on all but the hottest (90F+) days. I know you have a Tekin but they are similar kv and more importantly similar in size so your results should be similar. His truck has the old style LST1 version of the Claw tires which are heavier, plus the motor is well used so if anything his would get hotter than your Tekin. I had a Castle blower lying around so I put it on mostly for insurance since an 11yr old won't check temps.