ildonaldo wrote on 2019-03-11, 10:02:

Any idea where to get a matching replacement fan or - as an alternative

I am in the same situation, got this card used but it came with no heatsink nor fan. Did you solve it?

It would be great if we can find a compatible heatsink that allows the use of a Noctua NF-A4x10 FLX.

Often with these little fans - there will be a "sticker" on one side. Lift it and usually there's a little rubber "plug" (sometimes not - just the exposed cavity).
Under the plug is a small cavity containing a "C" ring which holds the main shaft through the main bearing/bushing ... these often dry up and begin making noise and eventually seize.

A drop of fine machine oil will almost always make it work "like new" - only if it's very worn will it be unrecoverable.

You usually don't have to remove the "C" ring - just a position the fan horizontally so the cavity with the "C" ring is up and give it just enough power to rotate slowly.

It's ok if you have to manually help it get started. With a drop of fine machine oil in the cavity where the "plug" would be, run it slowly for several minutes allowing the oil to work it's way into the bushing.
(You'll be able to tell as it frees up) - once it's running well, replace the plug. I usually just put a little square of "black" tape over the plug to help it stay in instead of trying to replace the sticker (you will want to remove it again someday)

These are usually called "permanently lubricated", but they do dry up - be prepared to repeat this "fix" every few years based on it getting noisy or slowing down.