There is no reason to leave the fan in the port for a high heat cook. Take it out. All you can do by leaving it in there is harm it. Especially given the scenario you describe whereby the fan is not being used. Take it out and plug the port, or leave it open for even more combustion air. Now on the other hand if you want to use it for the high heat cook, open the slider all the way, lay the pit probe outside the cooker somewhere, set the desired pit temp something well above ambient temp, and the fan will run non-stop the entire time. That should keep the fan and o-ring cool enough. But there is no reason nor need to do this for a high heat cook.