I have a Roku 4 that has been spontaneously rebooting and having sporadic communication issues (channels complain of "losing internet"). I run this unit with a wired connection and my internet/router are fine.
Are these possible symptoms of overheating? Should I open it up and see if it needs cleaning?
Along those lines, if this unit is dying, do the new Ultras (2018) have fans too? Or are they fanless?
The Roku 4 is the only unit with a fan. Some have commented on the noise the fan makes, but I have to say that I never noticed mine even had a fan. I had to hold it close to my ear to even hear it. I just gave it to my granddaughter to replace an old Blu Ray player for watching Amazon and Netflix. Been working fine for years. Of course, that doesn't mean that yours hasn't suffered some sort of failure.
Dan Roku Stick (3600), Ultra (4640), Premiere (3920), Insignia 720p Roku TV, Sharp 4K Roku TV, Nvidia Shield, Windows 10 Pro x64 running Serviio and Plex on a wired Gigabit network.