Is it possible to just buy some replacement fans, ofc I will get the same sized fans, not bigger or smaller and install them on my GPUs? Would that interfere in any way with the card?
Not just possible, it's often better.
You need a good fans (Delta Electronics), same size as heat sink. Not gpu fans, just fans.
Then remove everything from card except the heat sink and put a new ones firmly.
You need an external power supply for it, not from card but from PSU or MB. And it'll be noiser.
In my practice, the cooling is even better than the original solution. It also often cheaper and designed to work 24/7 at 100%, unlike original fans which worn out quite fast if set to 100%.
In case of turbine cooling new heat sink might be needed if it doesn't allow air intake from a top of it.
https://youtu.be/G5KdntuEbLMThanks a lot for the idea, mate ! I might try that in the near future. The problem is that my rig is currently in the middle of my living room, since I cannot afford moving to a bigger apartment, just because it's not worth it just for this rig to do this.
I am planning on expanding, depending on both CMC and GPU markets, and if I see some kind of a green light I might just do that and for sure I will try this technique.
Currently my fans are working at 35-40% load and the cards are around 45 Celsius, which is really good imo. I might buy an external fan just for the summer, because I do not have AC in my apartment and I will need to find a solution about that it.