venue 8 overheating

I have a Venue 8 and its forever overheating and shutting down.  I keep it in a folio but after a very short time its very hot.  I try to catch it before it shuts down, try turning it off for a few minutes to let it cool, but sometimes it doesn't help.

If this was my laptop I would know the issue, its the CPU overheating, as I'm sure is the case here.  But with a laptop its usually an easy fix, external usb fans or a good cleaning.  The tablet doesnt have USB so can't connect a fan, that I know for, and theres no vents to clean out.

Can anyone help me? Is anyone else having the same issue