|The fans on graphics cards often have cheap "oilite" sleeve bearings that have oil impregnated into the pores of the bearings. Eventually the interior hole of the bearing gets glazed and doesn't allow the impregnated oil to reach the shaft, then the bearings wear to the point that the bearings produce too much friction on the fan shaft, and you hear screeching or rattling noises, more likely to be noticed when the computer has sat for a while and has had a chance to cool down, when you then start up the computer, and after that the fan shaft often seizes in the bearings and the fan blade won't move, or at least, there's too much friction for the fan to start spinning. |
Oiling the bearings may work temporarily, but they were not intended to be oiled, and the only lasting solution is to replace the fan.
Measure the diameter of the fan blade and the distance between the centers of the holes for the mounting pins or mounting screws in millimeters, or convert to millimeters.
If you live in a reasonably large place, there are probably local places that have lots of computer related parts that may have a replacement fan that will mount on the heatsink, though it may not look the same as the original one.
If not, you will probably be able to find such a fan you can buy on a web site.
E.g. manufacturers that make custom (aftermarket) or replacement cpu fans often also make custom or replacement graphics card fans.
If you can find one that has one ball bearing, one sleeve bearing, or better still two ball bearings or two ceramic bearings, the bearings will last longer. (If the description or the label says ball bearing without an s, it probably has one ball bearing, one sleeve bearing.)
The replacement fan should have the same cfm (cubic feet per minute) rating or better - if that's not stated, if it looks similar and has the same diameter and depth of fan blade, it should spin at close to the same max speed or faster (see the specs of the graphics card if you need to) and draw close to the same amount of current - ma - or more.
If you use thermal grease - pure silicon grease with no additives - whitish, translucent, nearly clear when in a thin layer - between the heat sink and the graphics chip (or cpu), it never hardens