Home Internet router loses connection about every 5 days

I had mine on top of an A/C vent and it would die any time of day it felt like it.  I was not using the built-in wi-fi either.  The wireless modems in there can heat up pretty quick I think and there's just no active air flow through the device.  If you've got great signal it probably works but if you're far enough away that the device has to work but not far enough that it gives up, that's probably when things heat up.  I have never called tech support but it's my understanding that they are hard to get through to or not very knowledgeable.