did you try swapping them round positions and see if the same two rattled? I went all nanoxia at one point (1400rpm 140mm ones), and three of them needed RMAed from new (2 rattled, one visibly wobbled albeit quietly), and of the 8 i got 5 have since burnt out they’re lovely and quiet but i ended up changing out all but one (and keeping a spare) because taking radiators out to remove them was getting to be a hassle that happened too often. The exhaust is still one because that’s easy to swap out when it fails, as it already did once.
It’s not that i’ve anything against the rubber things in principal, but i found when i attached fans to radiators they were vibrating and quite loud, and if i got that problem with a screwed or bolted fan i could resolve it by tightening it, and that wasn’t an option with the rubber things. I think my server still uses them on it’s front intakes. None of that was with the nanoxia fans mind, i only tried them when i was replacing those with corsair sp140s.
I’m currently using mostly corsair ML140s; they’re quieter than the SP140s or the noctuas at the same speeds (400-800rpm) and no failures so far. I also swapped them out a couple of times when i had to take the radiators out for other stuff so hopefully they’ve all been running different amounts of time and won’t all fail within months of each other like the nanoxias did.
As I keep my case open most of the time now i’ve been pondering having all my radiators as intakes, but it’s such a faff to remove the top radiator and turn them all round. I know hot air rises but i remain unconvinced that it rises enough to factor into active cooling. But so far i lack the motivation to test it because of the number of screws involved.
Someone should make a simpler mechanic for mounting radiators and fans; they’re standard enough sizes.
On that, what’s with putting the controller for AiO coolers on the block? I feel like if it was on the radiator, where the fans are, there’d be less wiring. You’ve got hoses to the block anyway, so a wire from rad to block to power the pump and report back it’s speed seems like it’d be easier to hide/tidy than the multiple wires going from fans back to the block. I’m assuming there’s a good reason but i can’t figure it out.