My RT-AC86U is just over a year old (from Gearbest). Last week, it started hanging (Internet lost, unable to connect to the admin page even via Ethernet), fixed via power cycle only to crash again a random time later. The logs were not clear.

Thinking it was a bad flash, I tried updating the firmware again etc but no dice. Finally when I tried Merlin FW as a last resort, the temperature page alerted me that the router CPU was running extremely hot (99 degrees C!) and I finally noticed in the log that the CPU shut itself down due to thermal throttling. I'm not sure why I never noticed the line in the logs earlier (could be a line that Merlin FW added).

Communicating with Gearbest for RMA has been a bit frustrating (because of the language barrier) but they finally offered me 3 options:

1. Return the item to China at my own cost for free repair (which doesn't sound like RMA - it's not clear whether I'll be getting a new device or a refurbished one).
2. Keep the dud and get USD 30 credit in the Gearbest Wallet.
3. Keep the dud and buy a replacement from them at a "special" price of USD 150.

It's obviously a hardware problem (I have no idea what failed to trigger this series of events - I was running stock previously), but some comments seem to indicate the RT-AC86U has heat issues which means I may encounter it again.

I'm wondering whether installing those fans from Lazada that someone linked would make the dud usable, in which case it might make sense not to go for option 1.

I'm interested in what my fellow AC86U forumers think, especially those who have gone for RMA before, what was your experience etc?

That's the latest Asus firmware. Faced it now too. Mine is oldest one during review last year.

Decided to go buy the fan and go for the wallet credit. Didn't trust the RMA process could fix the issue (whatever the cause) and didn't want to risk buying another dud. Assuming the wallet credit doesn't expire (it shouldn't) I can wait until the hardware stabilizes before I fork out for another.

I think blow air in is a better position.

When you suck air out from behind, you actually suck air in from the top.

When you blow air in from behind, the air will hit the surface inside, reflected and continue to flow out from beside the fan, which you can actually feel it by putting your hand and feel the air flow. You will feel air blowing out from the router.