Originally posted by pentup I wonder if the weather sealing could be contributing to the problems? That is, if the motor is generating enough heat that can't escape, could it be damaging stuff? I know I was suddenly less enamored of the weather sealing on the K7 the first time I tried to use Live View during a heat wave.
IF that was the case, then a (cheap) heat-sink clamped on the motor body should disperse enough residual heat into the other lens components, not to cause a problem. However, having pulled my 16-50 apart and freed the jammed motor, I can tell you there's already a lot of air around the motor, and I really can't see that there'd be a problem dispersing heat from it. There's a great mass of glass and aluminium around it, too, to soak up heat generally, and the lens vents into the camera body.
Really, though, I think you'd have to be running the AF continuously and for a very significant length of time for motor heat build-up to be even in question.
As for weather sealing being an issue for Live View, the gaps in a non-sealed body are so small that convective heat transfer isn't likely to be an issue there, either. I could be wrong, but I'd like to see some real, scientific tests to prove it before I'd believe it. I'm not suggesting there isn't an issue with high ambient temperatures and Live View, just that I doubt it's the weather sealing causing it.