ASUS: I understand that you need a replacement for your ROG CROSSHAIR VIII HERO chipset fan, however it is a component level part and not a spare part so we cannot provide it to you.
ASUS: Personally, I would recommend you to send in your ROG CROSSHAIR VIII HERO for repair. Our records indicate that your unit is still covered by warranty up until 2022/07/30 and our repair facility should be able to address your concern.
ME: So, Asus produced a top of the line motherboard with precisely one moving part on it (and everyone screamed about how dumb that was) and when it fails I'm just supposed to throw the whole motherboard in the trash?
ME: Sorry for the cross post. Anyway, no I'm not sending it in for repair. You guys need to sell replacement parts or at least reference 3rd parties.
ME: Do you have any recommendations for a 3rd party replacement?
ASUS: I understand that it is easier to get a spare part and install it yourself, we do have that in our other components but it is not be applicable with chipset fans. I know that sending in the unit for repair may be inconvenient for you, but I assure you that this is the best way to address your concern. Please let me know if you are amenable for a repair.
ME: No. And Asus is dead to me.
If it were me I'd rather do the RMA but another option would be to remove that shroud and fan entirely and just throw some adhesive sinks on the hottest parts. As long as you have airflow in the area it's going to be way better than suffocating under a shroud with a dead fan.
FWIW, likely the reasoning for this decision was the layout meant things were sitting right next to the slot and difficult to keep cool. So they used this low profile shroud and fan to ensure cooling when the area is obstructed with a large card or receives no airflow due to a primarily liquid cooled system. But as you discovered, the Achilles heel is the fan. As long as you know what is going in the slot you can see if ditching the shroud and sticking some sinks will fit.